WO2013071180A1

WO2013071180A1 - Lignocellulose processing methods and related products

Info

Publication number: WO2013071180A1
Application number: PCT/US2012/064541
Authority: WO
Inventors: Robert Jansen; Eran BANIEL; Aharon Eyal; Noa Lapidot; James Alan LAWSON; Timothy Allen BAUER; Yael Miriam HAR-TAL; Shay Eliahu; Avital JACOB
Original assignee: Virdia Ltd
Current assignee: Virdia Ltd
Priority date: 2011-11-10
Filing date: 2012-11-09
Publication date: 2013-05-16
Anticipated expiration: 2014-05-10

Abstract

A method comprising: (a) extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream comprising hemicellulose sugars and impurities and an extracted substrate; (b) separating said first liquid stream from said extracted substrate; and (c) refining said first liquid stream to form a refined hemicellulose sugars stream; wherein said refining comprises at least one of: (i) liming to form a limed stream; and (ii) concentrating sugars in said first liquid stream to at least 40% and contacting with a water-soluble solvent to form a solvent-comprising refined stream.

Description

LIGNOCELLULOSE PROCESSING METHODS AND RELATED PRODUCTS

CROSS-REFERENCE TO RELATED APPLICATIONS:

In accord with the provisions of 35 U.S.C. § 119(e) and §363, this application claims the benefit of US 61/657,513 filed on 8 June 2012 by Robert JANSEN et al. and entitled "Lignocellulosic Processing Methods and Related Products"; US 61/644,697 filed on 9 May 2012 by Robert JANSEN et al. and entitled "Lignocellulosic Processing Methods and Related Products"; and US 61/558,374 filed on 10 November 2011 by Eran BANIEL et al. and entitled "Lignocellulose Processing Methods and Compositions Resulting Therefrom"; each of which is fully incorporated herein by reference. FIELD OF THE INVENTION

The invention relates to processing of lignocellulose.

BACKGROUND OF THE INVENTION

The carbohydrate-conversion industry currently ferments about 100 million tons of carbohydrates annually to provide fuel-grade ethanol. Millions of tons of carbohydrates are also fermented every year to provide food and feed products, such as citric acid and lysine. The carbohydrate-conversion industry also includes fermentation to industrial products, such as monomers for the polymer industry, e.g. lactic acid for the production of polylactide as well as chemical conversion of carbohydrates. Carbohydrates are an attractive and environment-friendly substrate since they are obtained from renewable crop resources. For example sucrose can be produced from sugar canes and glucose can be produced from corn and wheat starches.

However, crop resources such as sugar cane, corn and wheat are produced primarily for human consumption and/or as livestock feed. Increased consumption of these crop resources by the carbohydrate-conversion industry may impact food costs.

As an alternative, many renewable non-food resources are potential sources of soluble carbohydrates. The renewable non-food resources can generally be described as "lignocellulosic materials" or "woody materials". Lignocellulosic materials include wood and by-products of wood processing (e.g. sawdust, shavings) as well as residual plant material from agricultural products. Residual plant material from agricultural products includes processing by-products and field remains. Processing by-products include, but are not limited to, corn cobs, sugar cane bagasse, sugar beet pulp, empty fruit bunches from palm oil production, straw (e.g. wheat or rice), soy bean hulls, residual meals from the vegetable oil industry (e.g. soybean, peanut, corn or rapeseed) wheat bran and fermentation residue from the beer and wine industries. Field remains includes, but is not limited to, corn stover, post-harvest cotton plants, post-harvest soybean bushes and post-harvest rapeseed plants. Woody materials also include "energy crops" such as switch grass and/or broom grass, which grow rapidly and generate low-cost biomass specifically as a source of carbohydrates. Lignocellulosic materials contain cellulose, hemicellulose and lignin as their main components and also contain mineral salts (ashes) and organic compounds, such as tall oils. Despite the theoretical feasibility of realizing useful sugars from lignocellulosic materials, actual industrial production of such sugars has been limited.

SUMMARY OF THE INVENTION

Various embodiments of the invention relate to methods of producing sugars from a lignocellulosic substrate. In some exemplary embodiments of the invention, the method includes refining the sugars and/or processing sugars to produce conversion products.

One aspect of some embodiments of the invention relates to achieving a total yield of sugars corresponding to at least 90% of a theoretical yield of sugars available from the substrate while producing furfurals corresponding to less than 10% the theoretical yield of sugars. In some embodiments, this yield is achieved by performing two extractions under different conditions.

Another aspect of some embodiments of the invention relates to extracting first soluble sugars (e.g. hemicellulose sugars) prior to extraction of additional sugars (e.g. cellulose sugars) from the substrate. In some exemplary embodiments of the invention, extraction of hemicellulose sugars employs water or an aqueous solution, for example an aqueous solution of acid. Optionally, this extraction removes non-carbohydrate impurities from the substrate. In some embodiments, extraction of hemicellulose sugars includes mild hydrolysis. Alternatively or additionally, in some embodiments the extraction of cellulose sugars from the substrate includes contacting with a strong hydrolyzing solution. Examples of strong hydrolyzing solutions include concentrated mineral acids (e.g. HC1 and/or H₂SO₄) and reactive fluids. As used in this specification and the accompanying claims the term "reactive fluid" has the meaning ascribed to it in WO 2010/009343; paragraph [0058]:

The term "reactive fluid" used herein means a fluid that is at a temperature higher than the boiling point of the liquid state of the fluid under atmospheric pressure (1 atm). The reactive fluid may be a liquid, a gas, a supercritical fluid, or a mixture of these. For example, water at a temperature above 100 °C and under atmospheric pressure is considered a reactive fluid. Supercritical, near critical, and sub-critical fluids are reactive fluids, illustrative examples including but not limited to sub-critical water, near critical water, supercritical water, supercritical ethanol, and supercritical CO 2.

WO 2010/009343 is fully incorporated herein by reference. In some exemplary embodiments of the invention, extraction of hemicellulose sugars prior to extraction of cellulose sugars contributes to ease of extraction of cellulose sugars. Alternatively or additionally, in some embodiments extraction of hemicellulose sugars prior to extraction of cellulose sugars contributes to a reduction in degradation off hemicellulose sugars and/or cellulose sugars. Another aspect of some embodiments of the invention relates to analyzing a resultant liquid stream of hemicellulose sugars and/or an extracted substrate in order to calibrate conditions for a first extraction of a substrate. In some embodiments, the analysis considers non-carbohydrate components of the stream and/or the extracted substrate. Optionally, carbohydrate and/or non-carbohydrate 5 components of the stream are correlated to kinetics of a subsequent extraction.

Another aspect of some embodiments of the invention relates to analyzing kinetics of a subsequent extraction of a substrate in order to calibrate conditions for a first extraction of the substrate. In some embodiments, the analysis considers non-carbohydrate components of the stream.

It will be appreciated that the various aspects described above relate to solution of technical 10 problems related to sugar yield and/or sugar compositions and/or sugar purity in the context of lignocellulose processing.

Alternatively or additionally, it will be appreciated that the various aspects described above relate to solution of technical problems related to disposal of waste products and/or reagent recycling and/or management of unwanted byproducts in the context of lignocellulose processing.

15 As used in this specification and the accompanying claims the term "furfurals" indicates furfural, hydroxy-methyl furfural (HMF), products of furfural condensation and products of hydroxy- methyl furfural condensation.

As used in this specification and the accompanying claims, the term "water soluble solvent" indicates a solvent which has solubility in water of at least 60 grams solvent per 100 grams water at 20 25 degrees centigrade and/or a solvent in which at least 60 grams of water per 100 grams of solvent dissolve at the same temperature.

As used in this specification and the accompanying claims, the term "liming" indicates any process including contacting with lime, either as a solid, in solution, or in a slurry. As used in this specification and the accompanying claims the term "lime" indicates calcium-containing inorganic 25 materials (e.g. carbonates, oxides and hydroxides). For example, in some embodiments calcium oxide or calcium hydroxide serves as lime.

In some exemplary embodiments of the invention, there is provided a method including: (a) extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream including hemicellulose sugars and impurities and an extracted substrate; (b) separating the first liquid stream 30 from the extracted substrate; and (c) refining the first liquid stream to form a refined hemicellulose sugars stream; and the refining includes at least one of: (i) liming to form a limed stream; and (ii) concentrating sugars in the first liquid stream to at least 40% and contacting with a water-soluble solvent to form a solvent-comprising refined stream. In some embodiments, the water-soluble includes at least one member of the group consisting of acetone, methanol and ethanol. Alternatively 35 or additionally, in some embodiments the refining includes both the liming and the contacting with a water-soluble solvent. Alternatively or additionally, in some embodiments the method includes conducting the liming under conditions which form a slurry. Alternatively or additionally, in some embodiments the refining includes: contacting a refining aqueous stream including sugars and impurities with a water-soluble solvent, to produce a solvent-comprising refined stream and a precipitate; and separating the solvent-comprising refined stream from the precipitate. Alternatively or additionally, in some embodiments the method includes removing solvent from the solvent- comprising refined stream to generate a de-solventized refined stream. Alternatively or additionally, in some embodiments the refining includes polishing of the de-solventized refined stream to form a refined hemicellulose sugars stream. Alternatively or additionally, in some embodiments the liming includes contacting with C02. Alternatively or additionally, in some embodiments the liming includes separating solid from a slurry to form separated liming solid, and a limed stream including sugars. Alternatively or additionally, in some embodiments the method includes crystallizing xylose from at least one stream derived from the first liquid stream and separating the crystalline xylose from a mother liquor. Alternatively or additionally, in some embodiments the method includes chromatographically separating the first liquid stream to form a xylose enriched fraction. Alternatively or additionally, in some embodiments the method includes chromatographically separating the at least one stream derived from the first liquid stream to form a xylose enriched fraction. Alternatively or additionally, in some embodiments the method includes chromatographically treating the mother liquor to form a second xylose enriched fraction and a second xylose- depleted fraction. Alternatively or additionally, in some embodiments the method includes recycling the second xylose enriched fraction to the crystallizing. Alternatively or additionally, in some embodiments the method includes maintaining the pH of the first liquid stream between 3 and 9 during the refining. Alternatively or additionally, in some embodiments the method includes exposing the sugars to no pH greater than 10. Alternatively or additionally, in some embodiments the first liquid stream includes non-sugar organic matter, and the separated liming solid includes at least 10% of the non-sugar organic matter of the first liquid stream Alternatively or additionally, in some embodiments the first liquid stream includes tall oils, and the separated liming solid includes at least 10% of the tall oils in the first liquid stream. Alternatively or additionally, in some embodiments the method includes contacting the separated liming solid with an acid to form an organic phase; and separating the organic phase. Alternatively or additionally, in some embodiments the refining includes liming to form a limed stream and the method includes evaporating the limed stream to form a refining aqueous stream and vapor condensate. Alternatively or additionally, in some embodiments the method includes (i) contacting the refining aqueous stream with a water-soluble solvent, and the contacting results in a solvent-comprising refined stream and a precipitate, (ii) separating the solvent-comprising refined stream from the precipitate, (iii) removing solvent from the solvent-comprising refined stream to generate de-solventized refined stream; and (iv) polishing of the de-solventized refined stream to form a refined hemicellulose sugars stream. Alternatively or additionally, in some embodiments the method includes extracting additional sugars from the extracted substrate to form a second liquid stream including additional sugars, the second liquid stream being corrosive to stainless steel at the conditions of the extracting additional sugars; and refining the second liquid stream to produce a refined glucose stream. Alternatively or additionally, in some embodiments the method includes combining at least a fraction of one or more streams selected from the group consisting of the limed stream, the refining aqueous stream, the solvent-comprising refined stream, a de-solventized refined stream and the refined hemicellulose sugars stream with at least a fraction of the refined glucose stream during refining of the second liquid stream to form a partially refined sugar mixture. Alternatively or additionally, in some embodiments the method includes refining the partially refined sugar mixture to form a refined sugar mixture. Alternatively or additionally, in some embodiments the limed stream includes less than 3.0% non-sugar organic matter as a percentage of dissolved solids. Alternatively or additionally, in some embodiments the refining aqueous stream includes ash and the ash content of the solvent-comprising refined stream is less than 60% of the ash content of the refining aqueous stream. Alternatively or additionally, in some embodiments the method includes contacting the separated precipitate with a solution of a mineral acid; and the separated precipitate includes a salt of an organic acid. Alternatively or additionally, in some embodiments the de-solventized refined stream has a conductivity of less than 3000 micro- siemens. Alternatively or additionally, in some embodiments the refined hemicellulose sugars stream includes less than 10% non-sugar organic matter as a percentage of dissolved solids. Alternatively or additionally, in some embodiments the first liquid stream, the refining aqueous stream or both contain less than 5% of lignin in the lignocellulosic substrate. Alternatively or additionally, in some embodiments the lignocellulosic substrate is hardwood. Alternatively or additionally, in some embodiments the first liquid stream includes at least 40% of the hemicellulose sugars of the lignocellulosic substrate. Alternatively or additionally, in some embodiments a sugars concentration in the first liquid stream is between 1% and 10%. Alternatively or additionally, in some embodiments at least 50% of the sugars in the first liquid stream are in monosaccharide form Alternatively or additionally, in some embodiments the purity of sugars in the first liquid stream is greater than 40%. Alternatively or additionally, in some embodiments the purity of sugars in the first liquid stream is less than 70%. Alternatively or additionally, in some embodiments the first liquid stream includes at least 30% of an ash content of the substrate. Alternatively or additionally, in some embodiments the first liquid stream includes xylose and mannose and glucose and: (i) the w/w ratio of xylose + mannose to glucose is greater than 1.0; and (ii) the w/w ratio of sugars to furfural w/w is greater than 10:1. Alternatively or additionally, in some embodiments the first liquid stream includes acetic acid at a concentration of 0.002 to 0.2 %w/w. Alternatively or additionally, in some embodiments the first liquid stream includes xylose. Alternatively or additionally, in some embodiments at least 35% of the sugars in the first liquid stream are xylose on a weight basis. Alternatively or additionally, in some embodiments the method includes pulping the extracted substrate. Alternatively or additionally, in some embodiments the method includes the extracting includes maintaining at a temperature between 100°C and 160°C. Alternatively or additionally, in some embodiments the extracting is conducted at a pressure greater than 1 atmosphere. Alternatively or additionally, in some embodiments the solution includes a mineral acid. Alternatively or additionally, in some embodiments the method includes pelletizing the extracted substrate.

In some exemplary embodiments of the invention, there is provided a method including: (a) extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream including first soluble sugars and impurities and an extracted substrate; (b) separating the first liquid stream from the extracted substrate; and (c) extracting additional sugars from the extracted substrate to form a second liquid stream including second soluble sugars, the second liquid stream being corrosive to stainless steel at the conditions of the extracting additional sugars. In some embodiments, the method includes: (d) refining at least one of the first liquid stream and the second liquid stream to form refined sugars. Alternatively or additionally, in some embodiments the extracting a substrate includes maintaining under pressure at a temperature between 100°C and 160°C. Alternatively or additionally, in some embodiments the extracting a substrate includes contacting with an aqueous acid solution including H₂SO₃. Alternatively or additionally, in some embodiments aqueous acid solution includes H₂SO₃ and H₂SO₄. Alternatively or additionally, in some embodiments the extracting additional sugars includes contacting with an aqueous hydrolyzing solution of an acid. Alternatively or additionally, in some embodiments the extracting additional sugars includes contacting with an aqueous hydrolyzing solution including at least 30% wt. sulfuric acid. Alternatively or additionally, in some embodiments the ratio of acid to substrate in the hydrolyzing solution is smaller by at least 10% compared with the amount of acid required to reach a similar given sugars extraction yield when (c) is conducted at the same conditions in a method not including (a) and (b). Alternatively or additionally, in some embodiments the total yield of sugars in the first and second liquid streams corresponds to at least 90% of a theoretical yield. Alternatively or additionally, in some embodiments the extracting additional sugars includes contacting with a reactive fluid. Alternatively or additionally, in some embodiments the extracting additional sugars includes contacting at supercritical temperature, critical temperature or at near-critical temperature with an aqueous solution including an acid having pKa <4. Alternatively or additionally, in some embodiments the first liquid stream includes at least 40%> of the hemicellulose sugars of the lignocellulosic substrate. Alternatively or additionally, in some embodiments the sugars in the first liquid stream include at least 20%> of total extracted pentoses. Alternatively or additionally, in some embodiments at least 50%> of the sugars in the first liquid stream are in monosaccharide form Alternatively or additionally, in some embodiments the purity of sugars in the first liquid stream is greater than 40%>. Alternatively or additionally, in some embodiments the purity of sugars in the first liquid stream is less than 70%>. Alternatively or additionally, in some embodiments the first liquid stream includes at least 30% of the ash content of the lignocellulosic substrate. Alternatively or additionally, in some embodiments the first liquid stream includes acetic acid at a concentration of 0.002 to 0.2 %w/w. Alternatively or additionally, in some embodiments the first liquid stream includes xylose, mannose and glucose and: (i) the w/w ratio of xylose + mannose to glucose in the first liquid stream is greater than 1.0; and (ii) the w/w ratio of sugars to furfurals in the first liquid stream is greater than 10:1. Alternatively or additionally, in some embodiments the second liquid stream includes less than 60% of an ash content of the lignocellulosic substrate. Alternatively or additionally, in some embodiments the method includes refining both the first liquid stream and the second liquid stream. Alternatively or additionally, in some embodiments the method includes combining at least a portion of the first soluble sugars with at least a portion of the second soluble sugars prior to conclusion of the refining. In some exemplary embodiments of the invention, there is provided a first liquid stream produced by a method as described hereinabove. In some exemplary embodiments of the invention, there is provided a second liquid stream produced by a method as described hereinabove. In some exemplary embodiments of the invention, there are provided refined sugars produced by a method as described hereinabove. Alternatively or additionally, in some embodiments the lignocellulosic substrate is not contacted with a base prior to the extracting. Alternatively or additionally, in some embodiments the lignocellulosic substrate is not contacted with an acid prior to the extracting. Alternatively or additionally, in some embodiments the lignocellulosic substrate is not contacted with an organic solvent prior to the extracting. Alternatively or additionally, in some embodiments the lignocellulosic substrate is provided in particles, wherein the average size of 70%) of the substrate particles is Al, wherein the average size of 70%> of the extracted substrate particles is A2 and wherein A1/A2 is in the range between 0.6 and 1.1. Alternatively or additionally, in some embodiments the extracting additional sugars includes contacting with a concentrated solution of a strong acid, characterized by a contacting time that is at least 10%> shorter compared with the contacting time required to reach a similar given sugars extraction yield when (c) is conducted at the same conditions in a method not including (a) and (b). Alternatively or additionally, in some embodiments the method is characterized by generation of furfurals that is at least 10%> smaller compared with furfurals generation associated with a similar given sugars extraction yield when (c) is conducted at the same conditions in a method not including (a) and (b).Alternatively or additionally, in some embodiments the amount of methanol formed in the extracting additional sugars is smaller by at least 10%> compared with the amount of methanol formed with a similar given sugars extraction yield when (c) is conducted at the same conditions in a method not including (a) and (b). Alternatively or additionally, in some embodiments the extracted substrate includes less than 60%> of an ash content of the lignocellulosic substrate. Alternatively or additionally, in some embodiments the pentose content of the extracted substrate is less than 20%>. Alternatively or additionally, in some embodiments the extracting a lignocellulosic substrate includes applying a predetermined pressure- tem erature-time profile to the substrate. In some embodiments the predetermined pressure- temperature-time profile includes steam explosion. Alternatively or additionally, in some embodiments the predetermined pressure-temperature-time profile is characterized by severity factor of at least 3. Alternatively or additionally, in some embodiments the predetermined pressure- temperature-time profile is characterized by severity factor of less than 5. Alternatively or additionally, in some embodiments the predetermined pressure-temperature-time profile is characterized by severity factor in the range of 3.4 to 4.2. Alternatively or additionally, in some embodiments the extracting a lignocellulosic substrate includes applying a predetermined pressure- temperature-time profile and contacting with at least one of a volatile acid and a dilute acid solution and the contacting is conducted prior to the applying. Alternatively or additionally, in some embodiments the extracting a lignocellulosic substrate includes applying a predetermined pressure- temperature-time profile and contacting with an aqueous solution and the contacting is conducted subsequent to the applying. Alternatively or additionally, in some embodiments the extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream includes applying a predetermined pressure-temperature-time profile and contacting with a water-soluble solvent and the contacting is conducted prior to the applying. Alternatively or additionally, in some embodiments the extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream includes applying a predetermined pressure-temperature-time profile and contacting with a water-soluble solvent and the contacting is conducted subsequent to the applying.

In some exemplary embodiments of the invention there is provided a method including: (a) extracting a lignocellulosic substrate to form a first liquid stream including first soluble sugars and impurities and an extracted substrate; (b) separating the first liquid stream from the extracted substrate; and (c) hydrolyzing the extracted substrate with HC1 to form a second liquid stream including second soluble sugars, (d) refining the first liquid stream to form refined hemicellulose sugars; (e) refining the second liquid stream to form refined cellulose sugars. In some embodiments, the method includes combining at least a portion of the first soluble sugars with at least a portion of the second soluble sugars.

In some exemplary embodiments of the invention, there is provided a composition including (on a dry matter basis): (a) at least 30% xylose; (b) at least 50% hemicellulose sugars; (c) Ca hydroxide at at least 70% of saturation concentration of lime at room temperature and atmospheric pressure; and (d) less than 3% DCM soluble matter. In some exemplary embodiments of the invention, there is provided a composition including (on a dry matter basis): (a) at least 30% xylose; (b) at least 50% hemicellulose sugars; (c) Ca hydroxide at at least 70% of saturation concentration of lime at room temperature and atmospheric pressure; and (d) less than 3% non sugar organic matter. In some embodiments, such a composition is provided as a solution of at least 5% total dissolved solids (TDS).Alternatively or additionally, in some embodiments the composition has a conductivity of less than 3000 micro-siemens. Alternatively or additionally, in some embodiments the composition includes 0.002 to 0.2 %w/w acetic acid. In some exemplary embodiments of the invention, there is provided a composition including (on a dry matter basis): at least 85% xylose; and at least 1PPM lime. In some exemplary embodiments of the invention, there is provided composition including (on a dry matter basis): at least 85% xylose; and at least 1PPM water soluble solvent. In some exemplary embodiments of the invention, there is provided a composition including (on a dry matter basis): at least 80%) lime; and at least 10 PPM xylose. In some embodiments, the composition includes at least 1PPM of a solvent selected from the group consisting of methanol, ethanol and acetone. In some embodiments, the composition includes at least 1PPM acetone.

In some exemplary embodiments of the invention, there is provided a method for obtaining a high yield of sugars from a lignocellulosic substrate including: (a) extracting a lignocellulosic substrate to form a first liquid stream including at least 90%> of hemicellulose sugars and less than 10%) of cellulose (as soluble sugars) in the substrate and an extracted substrate; (b) hydro lyzing the extracted substrate to produce a second liquid stream containing at least 90%> of residual cellulose in the extracted substrate as soluble sugars; and (c) refining sugars from each of the first liquid stream and the second liquid stream; and the amount of hemicellulose sugars and cellulose sugars isolated from the lignocellulosic substrate is greater than 95% of the theoretical yield for the lignocellulosic substrate. In some embodiments, extracting to form a first liquid stream includes maintaining the biomass under pressure, at elevated temperature and in contact with an acid at a concentration up to 2%. Alternatively or additionally, in some embodiments the lignocellulosic substrate is pine. Alternatively or additionally, in some embodiments the hydrolyzing includes contacting the extracted substrate with an acid at a concentration greater than 30%> at ambient temperature and pressure.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although suitable methods and materials are described below, methods and materials similar or equivalent to those described herein can be used in the practice of the present invention. In case of conflict, the patent specification, including definitions, will control. All materials, methods, and examples are illustrative only and are not intended to be limiting.

As used herein, the terms "comprising" and "including" or grammatical variants thereof are to be taken as specifying inclusion of the stated features, integers, actions or components without precluding the addition of one or more additional features, integers, actions, components or groups thereof. This term is broader than, and includes the terms "consisting of and "consisting essentially of as defined by the Manual of Patent Examination Procedure of the United States Patent and Trademark Office. Thus, any recitation that an embodiment "includes" or "comprises" a feature is a specific statement that sub embodiments "consist essentially of and/or "consist of the recited feature. The phrase "adapted to" as used in this specification and the accompanying claims imposes additional structural/procedural limitations on a previously recited component/action.

The term "method" refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of architecture and/or computer science.

Unless specified otherwise, all % are %wt and all ratios are weight/weight.

As used in this specification and the accompanying claims the terms "extraction" and "extracting" indicate transfer of material from a solid substrate into a liquid stream which is a solution or a suspension and where the solvent is organic, aqueous or a mixture of the two. In some portions of some exemplary embodiments of the invention, the solvent is aqueous and is free from organic solvent.

As used in this specification and the accompanying claims the terms "sugar", "sugars" and "soluble sugars" indicates sugars with a solubility in water of at least 10% wt at 25 °C.

As used in this specification and the accompanying claims the terms "oligosaccharide" and

"polysaccharide" indicates non-monomeric sugars which are soluble and insoluble respectively according to the above definition of soluble sugars.

The terms "include", and "have" and their conjugates, as used herein, mean "including but not necessarily limited to".

The term "about", as used herein, refers to ± 10%, ±9%, ±8%, ±7%, ±6%, ±5%, ±4%, ±3%,

±2%, ±1%), of the stated amount.

As used in this specification and the accompanying claims the term "pulping" indicates separating cellulose fibers (as fibers) from a lignocellulosic substrate.

As used in this specification and the accompanying claims the term "impurity" or "impurities" refers to any non-carbohydrate material present in a sugar containing stream. This definition includes, but is not limited to minerals (e.g. ash and/or Ca and/or lime) and/or organic acids and/or pectin and/or sugar degradation products (e.g. furfurals).

As used in this specification and the accompanying claims the term "hemicellulose sugars" refers to pentoses (e.g. xylose, mannose, galactose, rhamnose and arabinose) and/or their corresponding acid forms and/or to soluble oligomers comprising these sugars.

As used in this specification and the accompanying claims the term "cellulose sugars" refers to glucose derived from cellulose as well as to soluble oligomers comprising glucose derived from cellulose. BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying figures. In the figures, identical or similar structures, elements or parts thereof that appear in more than one figure may be labeled with the same or similar references in the figures in which they appear. The figures are not necessarily drawn to scale. The attached figures are:

Fig. 1 is a simplified flow scheme illustrating methods according to various exemplary embodiments of the invention;

Fig. 2a is a simplified flow scheme illustrating a refining method according to some exemplary embodiments of the invention;

Fig. 2b is a simplified flow scheme illustrating a portion of the refining method of Fig. 2a in greater detail according to some exemplary embodiments of the invention;

Fig. 2c is a simplified flow scheme illustrating another portion of the refining method of Fig. 2a in greater detail according to some exemplary embodiments of the invention;

Fig. 2d is a simplified flow scheme illustrating an optional xylose recovery process which is included in the refining method of Fig. 2a according to some exemplary embodiments of the invention;

Fig. 3 is a simplified flow scheme illustrating an optional recycling loop in refining methods according to some exemplary embodiments of the invention;

Fig. 4 is a simplified flow scheme illustrating an optional liming solids treatment method according to some exemplary embodiments of the invention;

Fig. 5 is a simplified flow scheme illustrating convergent and divergent refining according to various exemplary embodiments of the invention;

Fig. 6a is a simplified flow scheme illustrating an exemplary optional precipitate treatment method according to some exemplary embodiments of the invention;

Fig. 6b is a simplified flow scheme illustrating an exemplary optional extracted substrate treatment method according to some exemplary embodiments of the invention; and

Fig. 7 is a simplified flow scheme illustrating methods according to various exemplary embodiments of the invention. DETAILED DESCRIPTION OF EMBODIMENTS

Introduction

Embodiments of the invention relate to processing of a lignocellulosic substrate to produce sugars and/or to refining of those sugars and/or processing of the sugars to produce a conversion product. Additional embodiments relate to the sugars and/or conversion products. Specifically, some embodiments of the invention can be used to increase efficiency of cellulose hydrolysis and/or to separate hemicellulose sugars from cellulose sugars.

Exemplary Methods

Fig. 1 is simplified flow scheme illustrating lignocellulose processing methods according to various exemplary embodiments of the invention indicated generally as 100. Depicted exemplary method 100 includes extracting 120 a lignocellulosic substrate 110 including hemicellulose and cellulose with an aqueous solution to form a first liquid stream 122 including first soluble sugars (e.g. hemicellulose sugars) and impurities and an extracted substrate 124. In some exemplary embodiments of the invention, the aqueous solution includes small amounts of an acid and/or an organic solvent. As used in this specification and the accompanying claims the term "extracted substrate" indicates material including at least 80%, at least 85% or at least 90%> of the lignin present in substrate 110 as un-dissolved lignin. In some embodiments, the aqueous solution used for extracting at 120 does not contain a sufficient amount of organic solvent for the organic solvent to extract lignin from lignocellulosic substrate 110. Optionally, first liquid stream 122 is an aqueous stream. In some embodiments, first liquid stream 122 contains no organic solvent. In some exemplary embodiments of the invention, first liquid stream 122 and/or refining aqueous stream 286 (Fig. 2a) contain less than 5%), less than 4, %, less than 3%, less than 2%, less than 1% or less than 0.5% of the lignin in lignocellulosic substrate 110. Alternatively or additionally, in some embodiments first liquid stream 122 contains less than 1%, less than 0.5%, less than 0.25% or less than 0.1% mineral acid.

In the depicted exemplary embodiment, method 100 includes separating first liquid stream

122 from extracted substrate 124 and extracting 130 additional sugars from extracted substrate 124 to form a second liquid stream 132 including second soluble sugars. In other exemplary embodiments of the invention, extracted substrate 124 is treated by pulping. In some exemplary embodiments of the invention second liquid stream 132 is corrosive to stainless steel at the conditions of extracting 130. In some embodiments, equipment used in performance of method 100 is adapted to resist corrosion by stream 132. Adaptation may be, for example by construction of relevant parts from corrosion resistant material(s). In some exemplary embodiments of the invention, method 100 includes refining 140 first liquid stream 122 and/or second liquid stream 132 to form refined sugars 142. In some embodiments, method 100 includes refining 140 both first liquid stream 122 and second liquid stream 132 to form refined sugars 142.

Referring again to Fig. 1, some exemplary embodiments of the invention relate to a method including extracting 120 a lignocellulosic substrate 110 with an aqueous solution to form a first liquid stream 122 including first soluble sugars (e.g. hemicellulose sugars) and impurities and an extracted substrate 124; separating first liquid stream 122 from extracted substrate 124 and refining 140 first liquid stream 122 to form refined hemicellulose sugars (depicted as refined sugars 142 in the figure). According to various exemplary embodiments of the invention refining 140 is conducted in different ways. Exemplary refining protocols are depicted in figs. 2a; 2b; 2c; 2d; 3; 4 and 5 and explained herein.

In some embodiments, depicted exemplary method 100 includes extracting 120 a lignocellulosic substrate 110 to form a first liquid stream 122 including at least 90% of hemicellulose sugars and less than 10%> of cellulose (as soluble sugars) in substrate 110 and an extracted substrate 124 and hydro lyzing (depicted as extracting 130) extracted substrate 124 to produce a second liquid stream 132 containing at least 90%> of residual cellulose in extracted substrate 124 as soluble sugars and refining 140 sugars from each of first liquid stream 122 and second liquid stream 132. According to some of these embodiments, the amount of hemicellulose sugars and cellulose sugars isolated from lignocellulosic substrate 110 is greater than 95% of the theoretical yield for the lignocellulosic substrate 110. In some embodiments, extracting 120 to form first liquid stream 122 includes maintaining substrate 110 under pressure, at elevated temperature and in contact with an acid at a concentration up to 2%>. Alternatively or additionally, in some embodiments substrate 110 is pine. Alternatively or additionally, in some embodiments hydrolyzing (depicted as extraction 130) includes contacting extracted substrate 124 with an acid at a concentration greater than 30%> at ambient temperature and pressure.

Exemplary refining method

Fig. 2a is a simplified flow plan, indicated generally as 145, depicting an exemplary way to perform refining 140 of Fig. 1. Refining 145 includes liming 210 first liquid stream 122 to form a limed stream 212 and evaporating 284 limed stream 212 to form a refining aqueous stream 286 and vapor condensate 288. In some embodiments, first liquid stream 122 is evaporated 284 directly (i.e. without liming 210) and the resultant stream serves as refining aqueous stream 286 as indicated by the dashed arrow. In some embodiments, evaporation 284 concentrates the sugars in stream 122 to at least 40%), at least 45%, at least 50%> or at least 55% or more by weight in stream 286. In some exemplary embodiments of the invention, liming 210 occurs prior to contacting 290 with a water soluble solvent to form solvent-comprising refined stream 292. In other exemplary embodiments of the invention, the order is reversed. In some embodiments, limed stream 212 includes volatile organic compounds, and vapor condensate 288 includes at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%), at least 80% or at least 90% or more of the volatile organic compounds present in limed stream 212. According to various exemplary embodiments of the invention the volatile organic acids include acetic acid and/or formic acid and/or furfurals and/or methanol. Alternatively or additionally, in some embodiments vapor condensate 288 includes methanol. Optionally, vapor condensate 288 serves as an energy source via anaerobic treatment. Optionally, organic matter in condensate 288 is treated in an anaerobic treatment to form biogas containing methane which is used as an energy source. In the depicted exemplary embodiment, refining 145 includes contacting 290 refining aqueous stream 286 with a water-soluble solvent (e.g. methanol and/or ethanol and/or acetone). Contacting 290 and separation 294, are also referred to as solvent treatment 143. In some embodiments, a sugars concentration in refining aqueous stream 286 is between 20% and 70% or 5 between 30% and 60%> prior to contacting 290.

In some embodiments, a stream (not depicted) containing a high concentration, of solvent (e.g. 95%) solvent/ [solvent+water]) is employed at contacting 290. From the standpoint of refining, increasing the solvent concentration at 290 contributes to an increase in refining efficiency. , However, any solvent employed at contacting 290 must be recovered by distillation (depicted as 10 removal 295) if it is to be recycled. From the standpoint of solvent recovery, increasing the solvent concentration at contacting 290 contributes to an increase in distillation cost. According to various exemplary embodiments of the invention the solvent concentration is set in consideration of both of these factors.

In the depicted embodiment, contacting 290 results in a solvent-comprising refined stream

15 292 and a precipitate 293. In some embodiments, at contacting 290, solvent/ (solvent+water) is about 60%), 70%), 80%), or 90%> or intermediate or greater percentages by weight. In some embodiments, at contacting 290, a ratio of solvent/sugar is about 5.0, 5.5, 5.7, 6.0 or 6.5 or intermediate or greater ratios. Alternatively or additionally, in some embodiments contacting 290 occurs at a temperature that is at least 10 °C below a boiling point of the solvent.

20 In some embodiments, precipitate 293 includes one or more salts (e.g. salts of cations removed from substrate 110 at extracting 120 and/or salts of carboxylic acids resulting from hydrolysis, e.g. acetic acid). Alternatively or additionally, in some embodiments precipitate 293 includes substantially no sugar. In some embodiments, refining 145 includes separating 294 solvent- comprising refined stream 292 from precipitate 293 and removing 295 solvent from solvent-

25 comprising refined stream 292 to generate a de-solventized refined stream 296. In the depicted exemplary embodiment, refining 145 includes polishing 298 of de-solventized refined stream 296 to form a refined hemicellulose sugars stream 299.

In some embodiments, removing 295 of the solvent includes distillation. Optionally, distillation of the water soluble solvent forms an azeotrope including the solvent and water. In some

30 embodiments removing, 295 generates a recycle stream (e.g. for use at contacting 290; not depicted).

In some embodiments, a solvent content of de-solventized refined stream 296 is less than 1.0%, less than 0.5%; less than 0.25% or less than 0.15%. Alternatively or additionally, in some embodiments a sugars content of de-solventized refined stream 296 and/or of refined hemicellulose sugars stream 299 is greater than 30%; greater than 32%; greater than 35% or greater than 37%.

35 Alternatively or additionally, in some embodiments refining 145 includes polishing 298 of de- solventized refined stream 296 to form a refined hemicellulose sugars stream 299. In some embodiments, polishing 298 includes contacting with an ion exchange resin (not depicted). Alternatively or additionally, in some embodiments polishing 298 includes contacting with at least one cation exchanger and/or contacting with at least one anion exchanger and/or contacting with a mixed-bed ion- exchanger. In some embodiments, contacting 290 contributes to a reduction in consumption of reagents used to regenerate the resin(s) employed at polishing 298 (e.g. acid for regeneration of cation exchanger and/or base for regeneration of anion exchanger). According to various exemplary embodiments of the invention this reduction in consumption of reagents used to regenerate the resin(s) is 10%, 15%, 20% or 25% or intermediate or greater percentages.

Although refining is described in the context of stream 122 as an example, similar refining processes can be conducted in stream 132 or on a mixture of streams 122 and 132.

Exemplary refining efficiency

Various exemplary embodiments of the invention relate to refining 140 at least one of first liquid stream 122 and/or second liquid stream 132 to form refined sugars 142. According to these embodiments of the invention, if a ratio of sugars to impurities in the stream to be refined (122 and/or 132) is defined as A and a ratio of sugars to impurities in refined sugars 142 is defined as B, then a ratio of B:A is indicative of a degree of refining. According to various exemplary embodiments of the invention, B:A is 10, 15, 20, 25, 30, 35 or intermediate or greater values. For example, in various embodiments, B: A is between 10 and 34, between 10 and 30, between 10 and 25, between 10 and 20, between 10 and 15, between 20 and 35, between 20 and 30 or between 20 and 25. As depicted in Figs. 2a and 2b and 2c, refining 140 includes two or more processes (e.g. 141 and 143) in some embodiments of the invention.

Exemplary solvent treatment

Fig. 2b is a simplified flow plan of an exemplary solvent treatment process, indicated generally as 143. Plan 143 depicts the solvent treatment of refining 145 (Fig. 2a) in greater detail according to some embodiments of the invention. The relationship between 143 and 145 is indicated graphically by dashed rectangle 143 in Fig. 2a.

In Fig. 2b, solvent treatment 143 includes contacting 290 a refining aqueous stream 286 including sugars and impurities with a water-soluble solvent 289, to produce a solvent-comprising refined stream 292 and a precipitate 293 and separating 294 solvent-comprising refined stream 292 from precipitate 293. According to various exemplary embodiments of the invention refining aqueous stream 286 includes first liquid stream 122 and/or limed stream 212. Alternatively or additionally, in some embodiments precipitate 293 contains salts of one or more carboxylic acids (e.g. acetic acid).

In some exemplary embodiments of the invention, the water soluble solvent 289 employed at contacting 290 comprises, consists essentially of, or consists of one or more alcohols and/or ketones and/or aldehydes and/or esters with solubility greater than 30 grams per 100 grams water at 25°C. In some embodiments, the water-soluble solvent comprises, consists essentially of, or consists of acetone and/or methanol and/or ethanol. In some embodiments, the water soluble solvent 289 comprises, consists essentially of, or consists of acetone. In other embodiments of the invention, the water soluble solvent 289 comprises, consists essentially of, or consists of ethanol. In other exemplary embodiments of the invention, the water soluble solvent 289 comprises, consists essentially of, or consists of methanol.

Alternatively or additionally, in some embodiments refining aqueous stream 286 is derived from limed stream 212 (e.g. by evaporation 284; Fig. 2a). Alternatively or additionally, in some embodiments contacting 290 is at a temperature between 20°C and 70°C, 25°C and 60°C or 30°C and 55°C. Alternatively or additionally, a sugars concentration in refining aqueous stream 286 is greater than 30, greater than 35%, greater than 40%>, greater than 45% or greater than 50%. Alternatively or additionally, in some embodiments a sugars concentration in refining aqueous stream 286 is less than 70%) or less than 60%>. Optionally, a sugars concentration in refining aqueous stream 286 is between 35%) and 70% or between 40% and 60%. Alternatively or additionally, in some embodiments a pH of refining aqueous stream 286 is between 4 and 7, between 4.5 and 6, between 5 and 5.5 or about 5.2 (inclusive of the numbers specified as the endpoints of the ranges). In some embodiments, refining aqueous stream 286 includes solids and the amount of solids increases as a result of contacting 290 with solvent 289. According to various exemplary embodiments of the invention the amount of increase is a function of salt content of stream 286. In some embodiments, a large fraction of the salt content of stream 286 precipitates at contact 290. In some embodiments, contacting 290 with solvent 289 includes contacting of refining aqueous stream 286 with a recycled stream (not depicted) including the solvent and water. In some exemplary embodiments of the invention, organic solvent 289 is acetone and the recycled stream is about 90% acetone and about 10% water. For example, the recycled stream in some embodiments is 70 to 95 % acetone or 80 to 92% acetone with the remainder being primarily water. Optionally, the recycled stream includes small amounts of another solvent.

In other exemplary embodiments, organic solvent 289 is ethanol and the recycled stream is about 80%) ethanol and about 20% water. For example, the recycled stream is some embodiments is 65 to 90 % ethanol or 70 to 80% ethanol with the remainder being primarily water. Alternatively or additionally, in some embodiments a ratio between the recycled stream and refining stream 286 is between 0.5 and 5, between 0.75 and 4.5 or between 1 and 4 (inclusive of numbers designating the endpoints of the ranges). In some exemplary embodiments of the invention, separating 294 solvent- comprising refined stream 292 from precipitate 293 includes filtration.

Exemplary liming process

Fig. 2c is a simplified flow plan of an exemplary liming process indicated generally as 141. Plan 141 depicts the liming portion of refining 145 (Fig. 2a) in greater detail according to some embodiments of the invention. The relationship between 141 and 145 is indicated graphically by dashed rectangle 141 in Fig. 2a. In Fig. 2c, refining 145 includes liming 210 (i.e. contacting with lime 208) to form a limed stream 212. In some exemplary embodiments of the invention, refining 145 includes both liming 210 and contacting 290 with a water-soluble solvent as depicted in Fig. 2a. In some embodiments, liming 210 occurs before contacting 290. In other embodiments, liming 210 occurs after contacting 290. In some exemplary embodiments of the invention, the water-soluble solvent 289 at 290 includes acetone and/or methanol and/or ethanol. Optionally, the solvent is acetone. Optionally, the solvent is ethanol. Optionally, the solvent is methanol. In some exemplary embodiments of the invention, liming 210 is conducted under conditions which form a slurry. In some exemplary embodiments of the invention, the solid in the slurry is at least partially lime. Alternatively or additionally, in some embodiments liming 210 includes contacting with CO₂ 209 and/or separating 214 solid from a slurry to form separated liming solid 215 and limed stream 212 including sugars. In some exemplary embodiments of the invention, limed stream 212 is rich in hemicellulose sugars.

Optional xylose recovery process

Fig. 2d is a simplified flow scheme illustrating an optional xylose recovery process indicated generally as 147. In some exemplary embodiments, xylose recovery process 147 is included in the refining method of Fig. 2a.

According to some embodiments of depicted exemplary xylose recovery process 147 one or more streams derived from first liquid stream 122 and/or first liquid stream 122 itself are subjected to chromatographic separation 250 as indicated by arrow (A). In the depicted "A" type embodiments, separation 250 produces a xylose enriched fraction 252 and a xylose depleted fraction 253. According to these embodiments, crystallization 260 of xylose enriched fraction 252 produces crystalline xylose 262 and a mother liquor (ML) 310. According to various exemplary embodiments, the one or more streams derived from first liquid stream 122 include lime stream 212 and/or refining aqueous stream 286 and/or solvent-comprising refined stream 292 and/or de-solventized refined stream 296 and/or refined hemicellulose sugars stream 299. In some embodiments, first liquid stream 122 proceeds directly to chromatographic separation 250.

According to some embodiments of depicted exemplary xylose recovery process 147 one or more streams derived from first liquid stream 122 (i.e. 212, 286,292, 296 and/or 299) and/or first liquid stream 122 are crystallized 260 directly (i.e. without chromatographic separation 250) as indicated by arrow (B). In the depicted "B" type embodiments, crystallization 260 of the one or more streams produces crystalline xylose 262 and a mother liquor (ML) 310. In some embodiments, first liquid stream 122 proceeds directly to crystallization 260.

In some exemplary embodiments of the invention, some streams are processed by the "A" route including chromatographic separation 250 and other streams are directly crystallized 260 according to the "B" route. In some exemplary embodiments of the invention, refining 145 (Fig. 2a) includes crystallizing 260 (Fig. 2d) xylose 262 from at least one stream derived from first liquid stream 122 and separating crystalline xylose 262 from a mother liquor 310.

In some exemplary embodiments of the invention, the at least one stream derived from first liquid stream 122 is processed by chromatographically separating 250 first liquid stream 122 to form a xylose enriched fraction 252. Alternatively or additionally, in some embodiments xylose recovery process 147 includes chromatographically separating 250 the at least one stream derived from first liquid stream 122 to form xylose enriched fraction 252.

Exemplary optional mother liquor (ML) treatment

Fig. 3 is a simplified flow scheme illustrating an optional recycling loop in refining methods according to some exemplary embodiments of the invention indicated generally as 300. Loop 300 is employed in conjunction with xylose recovery process 147 in some embodiments. More specifically, loop 300 treats mother liquor 310 resulting from crystallization 260 (Fig. 2d).

In the depicted exemplary embodiment, loop 300 includes chromatographically treating 320 mother liquor 310 to form a second xylose enriched fraction 322 and a second xylose depleted fraction 323. In some embodiments, second xylose enriched fraction 322 is recycled 330 to crystallization 260 described above.

Exemplary liming solid treatment

Fig. 4 is a simplified flow scheme illustrating an optional liming solids treatment method according to some embodiments indicated generally as 400. The depicted exemplary method includes contacting 410 separated liming solid 215 with an acid to form an organic phase 422 and separating 420 organic phase 422 from an organics-depleted lime 423. In some embodiments, organics-depleted lime 423 is re-cycled to liming 210.

According to various exemplary embodiments of the invention separating 214 (Fig. 2c) liming solid 215 includes filtration and/or centrifugation. Alternatively or additionally, in some embodiments separating 420 organics-depleted lime 423 includes centrifugation. Alternatively or additionally, in some embodiments separated liming solid 215 and/or separated organics-depleted limed 423 are washed with water. In some embodiments, the wash water is mixed with the first liquid stream 122 and/or is used to form the lime slurry. According to various exemplary embodiments of the invention various acids (e.g. HC1 or H₂SO₄) are used at contacting 410.

In some embodiments, contacting 410 liming solid 215 with acid forms a slurry. Optionally, a pH in the liquid fraction of the slurry is less than 7, less than 6.5, less than 6, less than 5.5, or less than 5.0. Alternatively or additionally, a pH in the liquid fraction of the slurry is greater than 3, greater than 3.5, greater than 4 or greater than 4.5. Exemplary refining of the second liquid stream

Fig. 5 is a simplified flow scheme indicated generally as 500 illustrating convergent and divergent refining of first and second liquid streams (122 and 132 respectively; Fig. 1) according to various exemplary embodiments of the invention. Fig. 5 provides additional details and/or options for combining 550 various streams during refining 140.

Referring to Fig. 1 and Fig. 5 concurrently, in some exemplary embodiments of the invention the method includes extracting 130 additional sugars from extracted substrate 124 to form a second liquid stream 132 including additional (cellulose) sugars. In some embodiments, second liquid stream 132 is corrosive to stainless steel at the conditions of extracting 130.

In the depicted exemplary embodiment of Fig. 5, the method includes refining 140 (Fig. 1) second liquid stream 132 to produce a refined glucose stream 542.

Fig. 5 also depicts exemplary embodiments which include combining 550 at least a fraction of limed stream 212 and/or refining aqueous stream 286 and/or solvent-comprising refined stream 292 and/or de-solventized refined stream 296 and/or refined hemicellulose sugars stream 299 with at least a fraction of refined glucose stream 542 during refining 140 of second liquid stream 132 to form a partially refined sugar mixture 552. In some exemplary embodiments of the invention, the method includes refining 560 partially refined sugar 552 mixture to form a refined sugar mixture 562. According to various exemplary embodiments of the invention refining 560 includes liming and/or evaporating and/or contacting with a water-soluble solvent and/or chromatographic separation and/or ion-exchange as described herein in the context of refining 140 (see Figs. 2a; 2b; 2c; 2d; 3 and 4 and corresponding textual explanations).

Exemplary first extraction conditions

In some exemplary embodiments of the invention, extracting sugars 120 includes maintaining at a temperature of 100 °C to 160 °C with an aqueous solution (hot wash). In some embodiments, the hot wash is conducted at a pressure greater than 1 atmosphere. In various embodiments, extracting sugars 120 includes maintaining under pressure at a temperature in the range of 100 °C to 160 °C; 110 °C to 150 °C; 120 °C to 145 °C or 130 °C to 140 °C. Alternatively or additionally, in some embodiments the solution includes a mineral acid (e.g. HC1 and/or H₂SO₄). For example, in some embodiments extracting sugars 120 includes maintaining at a temperature of 130 °C to 140 °C for 1 to 4 hours, 2 to 3 hours or 2.5 to 3 hours, followed by slow cooling.

In other exemplary embodiments of the invention, extracting sugars 120 includes maintaining at a temperature of 140 °C to 150 °C for 0.5 to 2 hour or 0.75 to 1.5 hours followed by slow cooling.

In some embodiments, the temperature changes during extracting 120. Alternatively or additionally, in some embodiments, the pressure is about that of water vapors at the selected temperature. According to various exemplary embodiments of the invention maintaining is for a time between 0.1 hour and 10 hours, 0.5 and 8 hours; 1 and 6 hours; 2 to 5 hours or 80 minutes to 120 minutes.

In some embodiments, at the end of the time at the elevated temperature, the temperature is lowered and the pressure is reduced. Optionally, that is done by flashing (e.g. using GEA Barr-Rosin Flash Dryer; GEA Process Engineering Ltd., Maidenhead, Berkshire, UK). Alternatively or additionally, in some embodiments, pressure release is done gradually (as opposed to the rapid release characteristic of steam explosion). In some embodiments, the extracted substrate is washed with water and dried after depressurizing. Drying can be, for example, with a Swiss Combi type drier.

In some embodiments, the wash water is used to prepare an aqueous acid solution for a subsequent round of extracting 120. In some embodiments, extracted substrate 124 is not contacted with an organic solvent. In some embodiments, during extracting 120 lignocellulosic substrate 110 is contacted with sufficient aqueous solution, optionally water, to cover it. For example, if lignocellulosic substrate 110 is provided as wood, the wood/water ratio (dry weight basis) can be 0.05 to 0.5; 0.07 to 0.3 or 0.08 to 0.2. Alternatively or additionally, in some exemplary embodiments of the invention lignocellulosic substrate 110 is contacted with steam prior to extracting 120.

In some embodiments, extracting 120 includes contacting with an aqueous acid solution. Optionally, provision of acid in the aqueous solution at 120 contributes to an increase in the proportion of monomeric sugars in first liquid stream 122. According to various embodiments, the acid in the aqueous solution at 120 includes HC1 and/or H₂SO₄ and/or H₂SO₃ (e.g. as SO₂ dissolved in water) and/or H₃PO₄ and/or HNO₃. In some embodiments, extracting 120 includes contacting with an aqueous acid solution including H₂SO₃. In some embodiments, extracting 120 includes contacting with an aqueous acid solution including both H₂SO₄ and H₂SO₃. In some embodiments, a total acid concentration in aqueous acid solution at 120 is in the range of 0.1% to 2.0%; 0.2% to 1.5%; 0.3% to 1.2% or 0.4% to 1.0% (inclusive).

According to various embodiments, the aqueous acid solution used for extracting 120 and/or first liquid stream 122 is non-corrosive to stainless steel at temperature conditions of extracting 120 (exemplary temperature conditions for extracting 120 recited above).

Exemplary second extraction conditions

In some exemplary embodiments of the invention, extracting 130 includes contacting with an aqueous hydrolyzing solution of an acid. According to various embodiments, the aqueous hydrolyzing solution includes at least 30%, at least 40%, at least 50%, at least 60%, at least 70% or 80% wt. or intermediate or greater percentages of sulfuric acid.

In some embodiments, the contacting of extracted substrate 124 with the aqueous hydrolyzing solution is conducted at ambient pressure and/or at a temperature lower than 20°C. Alternatively or additionally, in some embodiments the acid includes a strong mineral acid, for example HC1 and/or H₂SO₄ and/or H₃PO₄ and/or HNO₃. In some embodiments, the strong mineral acid is HC1. In some embodiments, the HC1 concentration is greater than 30%, greater than 35%, greater than 38%, greater than 40%), greater than 41%> or greater than 42%. In some embodiments, the contacting with the hydro lyzing solution is done in accordance with methods and/or using equipment, described in copending application PCT/US2011/057552 which is fully incorporated herein by reference.

In some cases, the ratio of acid to substrate 110 in the aqueous hydro lyzing solution of acid used at 130 is smaller by at least 10%> in exemplary method 100 compared with that ratio required to reach a similar given sugars extraction yield in a method not including extracting 120 conducted under the same conditions. In other words, practice of extraction 120 contributes to a reduction in the requirement for acid at 130 in some embodiments.

In some embodiments of method 100 the total yield of sugars in first and second liquid streams 122 and 132 corresponds to at least 90%>; at least 95%; at least 98% or at least 99% of a theoretical yield of sugars available from substrate 110. Alternatively or additionally, in some embodiments the total furfurals in first and second liquid streams 122 and 132 corresponds less than 10%; less than 5%; less than 2% or less than 1% of a theoretical yield of sugars available from substrate 110. The theoretical yield is a calculated value based upon complete conversion of polysaccharides in lignocellulosic substrate 110 to water-soluble sugars. In some embodiments, this yield is achieved with no additional extractions beyond 120 and 130.

In some embodiments, extracting 130 includes contacting with a reactive fluid. In some embodiments, extracting 130 includes contacting with both acid and reactive fluid in any order or concurrently. In some embodiments, extracting 130 includes contacting at supercritical temperature, critical temperature or at near-critical temperature with an aqueous solution including an acid having pKa <4. In some embodiments, this contacting occurs in the presence of an organic solvent (e.g. contacting is with an acid/solvent mixture).

Exemplary liming conditions

Referring again to Figs. 2a and 2c, in some exemplary embodiments of the invention liming

210 includes contacting (e.g. mixing) first liquid stream 122 with a suspension of lime in water. In some embodiments, the mixing is gentle. In some embodiments, a ratio between the suspension of lime in water and first liquid stream 122 is 0.003, 0.005, 0.007, 0.01, 0.012, 0.015 or intermediate or greater values. Alternatively or additionally, in some embodiments the amount of lime in the lime suspension is greater than stoichiometric to an acid content in the first liquid stream 122 (e.g. 110%), 120%), 130%) or 140%) or intermediate percentages of the stoichiometric amount). Alternatively or additionally, in some embodiments CO₂ 209 is bubbled through the mixture of first liquid stream 122 and the suspension of lime in water. Alternatively or additionally, in some embodiments liming 210 is conducted at about ambient temperature. Alternatively or additionally, in some embodiments mixing of first liquid stream 122 and the suspension of lime in water continues for 1 minute to 3 hours, 10 minutes to 2 hours or 20 minutes to 1 hour. Alternatively or additionally, in some embodiments lime and CO₂ addition(s) are conducted so that the pH in the resultant mixture is kept during the majority of the mixing time at less than 9, less than 8.8, less than 8.6, less than 8.4 or intermediate or lower pH values. Alternatively or additionally, in some embodiments lime and CO₂ addition(s) are conducted so that the pH in the resultant mixture is kept during the majority of the mixing time at higher than 7.5, higher than 7.8, higher than 8.0, higher than 8.2 or intermediate or higher pH values.

Exemplary extraction conditions

Referring again to Fig. 1, in some embodiments, extracting 120 includes applying a predetermined pressure-temperature-time profile to lignocellulosic substrate 110. In some embodiments, the predetermined pressure-temperature-time profile includes maintaining lignocellulosic substrate 110 under super-atmospheric pressure. For example, in some embodiments, the predetermined pressure-temperature-time profile includes steam explosion. According to various exemplary embodiments of the invention the predetermined pressure-temperature-time profile is characterized by severity factor of 3, 3.2, 3.4, 3.6, 3.8, or even at least 4.0. As used in this specification and the accomp indicates:

where t indicates time and T indicates temperature.

Alternatively or additionally, in some embodiments, the predetermined pressure-temperature- time profile is characterized by severity factor of less than 5, 4.8, 4.6, 4.4, or 4.2 or intermediate or lower values.

Alternatively or additionally, in some embodiments, the predetermined pressure-temperature- time profile is characterized by severity factor of between 3 and 5 or between 3.2 and 4.5 or between 3.2 and 4.2.

In some exemplary embodiments of the invention, extracting 120 includes applying a predetermined pressure-temperature-time profile as described herein to substrate 110 and contacting substrate 110 with at least one of a volatile acid and a dilute acid solution and the contacting with acid is conducted prior to the applying of the predetermined pressure-temperature-time profile. Examples of suitable volatile acids include, but are not limited to sulfurous acid (SO₂) and acetic acid. For example, the volatile acid is sprayed on substrate 110 prior to steam explosion in some embodiments. Alternatively or additionally, in some embodiments extracting 120 includes contact with a dilute acid solution. According to various exemplary embodiments of the invention the acid concentration is less than 1.0%, 0.8%, 0.7%, 0.6% or less than 0.5% wt.

In some exemplary embodiments of the invention, extracting 120 includes applying a predetermined pressure-temperature-time profile to substrate 110 and subsequently contacting it with an aqueous solution. For example, a steam exploded substrate may be washed with an acid solution or an acetone solution, optionally containing an acid (e.g. a volatile acid). In some exemplary embodiments of the invention, extracting 120 includes applying a predetermined pressure-temperature-time profile to substrate 110 after contacting it with a water- soluble solvent. For example, acetone can be applied to the substrate and an "acetone explosion" can be performed instead of steam explosion.

5 Exemplary first liquid stream compositions

In some exemplary embodiments of the invention, first liquid stream 122 includes at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 98% of the hemicellulose sugars of substrate 110. Hemicellulose is a polysaccharide-polymer of monosaccharide(s). Extracting 120 transfers sugars into the solution. The sugars transferred to the

10 solution result from some hydro lyzing of the hemicellulose polysaccharide. The hydrolyzing may form monosaccharides and/or oligosaccharides, all of which are fractions of the polysaccharide. As used in this specification and the accompanying claims the term "at least XX% of the hemicellulose sugars" means that the monosaccharides forming the original hemicellulose are present (as monosaccharides and/or oligosaccahrides) in the first stream 122. In some embodiments, first liquid

15 stream 122 includes xylose. According to various embodiments xylose is at least 35%, at least 45%, at least 50%), at least 55%, at least 60%, at least 65% or at least 70% of the total sugars in first stream 122 (by weight).

Alternatively or additionally, in some embodiments, first stream 122 includes less than 50%, less than 40%, less than 30%, less than 20% or less than 10% glucose equivalent of the cellulose in

20 substrate 110. Alternatively or additionally, the total sugar concentration in first stream 122 is in the range of 1% to 10%, 2% to 8% or 3% to 6%.

Alternatively or additionally, in some embodiments a ratio between hemicellulose sugars and glucose in first liquid stream 122 is greater than 3, greater than 5, greater than 8, greater than 10, greater than 12 or greater than 15 on a weight basis. Alternatively or additionally, in some

25 embodiments the sugars in first stream 122 include at least 20%, at least 40%, at least 60%, at least 80%), at least 90%, at least 95% or at least 99% of total extracted pentoses (i.e. pentoses in streams 122 and 132). Alternatively or additionally, in some embodiments at least 50%, at least 60%, at least 70%), at least 80%, at least 85%, at least 90% or at least 95% of the sugars in first stream 122 are in monosaccharide form. Alternatively or additionally, in some embodiments the purity of sugars in first

30 stream 122 is greater than 40%, greater than 45%, greater than 50% or greater than 60% (i.e. at least the specified percentage of total dissolved solids is sugars). Alternatively or additionally, in some embodiments the purity of sugars in first stream 122 is less than 70%; less than 65%; less than 60%; less than 55%; less than 50%; less than 45%; less than 43% or less than 42% expressed as sugars/total solutes. Alternatively or additionally, in some embodiments first liquid stream 122 includes at least

35 30%; at least 40%; at least 50%; at least 60%; at least 70%; at least 80% or at least 90% of an ash content of substrate 110. Alternatively or additionally, in some embodiments first liquid stream 122 includes at least 30%; at least 40%; at least 50%; at least 60%; at least 70%; at least 80% or at least 90%) of a calcium ion content of substrate 110. Alternatively or additionally, in some embodiments first liquid stream 122 includes at least 30%; at least 40%; at least 50%; at least 60%>; at least 70%; at least 80%) or at least 90% of a divalent cations content of substrate 110. Alternatively or additionally, 5 in some embodiments first liquid stream 122 includes at least 30%; at least 40%; at least 50%; at least 60%; at least 70%; at least 80% or at least 90% of the acetate functions of substrate 110. Alternatively or additionally, in some embodiments first liquid stream 122 includes at least 30%; at least 40%; at least 50%; at least 60%; at least 70%; at least 80% or at least 90% of a pectin content of substrate 110. In some embodiments, pectin in stream 122 is at least partially present as degradation products (e.g.

10 methanol and/or galactauronic acid). Alternatively or additionally, in some embodiments first liquid stream 122 includes at least 30%; at least 40%; at least 50%; at least 60%; at least 70%; at least 80% or at least 90% of a pectin content of substrate 110 as a pectin conversion product (e.g. methanol and/or galactauronic acid). Alternatively or additionally, in some embodiments first liquid stream 122 includes at least 30%; at least 40%; at least 50%; at least 60%; at least 70%; at least 80% or at least

15 90%) of a lipophilic material content of substrate 110. Alternatively or additionally, in some embodiments first liquid stream 122 includes at least 30%; at least 40%; at least 50%; at least 60%; at least 70%; at least 80% or at least 90% of a pentose content of substrate 110. Alternatively or additionally, in some embodiments first liquid stream 122 includes at least 30%; at least 40%; at least 50%; at least 60%; at least 70%; at least 80% or at least 90% of a mannose content of substrate 110.

20 Alternatively or additionally, in some embodiments substrate 110 includes lignin and first stream 122 includes phenolic compounds in an amount of less than 10%, less than 8%, less than 6%, less than 4% or less than 2% of the lignin in the substrate.

Alternatively or additionally, in some embodiments first liquid stream 122 includes acetic acid in an amount equivalent to at least 40%, at least 50%, at least 60%, at least 70%, at least 80% of

25 the acetate function in substrate 110.

Alternatively or additionally, in some embodiments first liquid stream 122 includes acetic acid in an amount equivalent to at least 40%, at least 50%, at least 60%, at least 70% or at least 80% of the acetate function in a conversion product of substrate 110.

Alternatively or additionally, in some embodiments first liquid stream 122 includes acetic

30 acid at a concentration of 0.002 to 0.5%; 0.1% to 0.5%; 0.15% to 0.37% and 0.2 to 0.3%). Optionally, first liquid stream 122 includes acetic acid at a concentration of 0.002 to 0.2 % w/w.

Alternatively or additionally, in some embodiments first liquid stream 122 includes formic acid at a concentration of at least 0.05%; at least 0.025%>; at least 0.01% or at least 0.005%).

Alternatively or additionally, in some embodiments first liquid stream 122 includes furfural

35 and/or its degradation products at a concentration of between 0.002%) and 0.25%; 0.003 and 0.2% and 0.004% and 0.15%. Alternatively or additionally, in some embodiments first liquid stream 122 includes mineral acid at a concentration of 0.1% to 2.0%; 0.15% to 1.5%; 0.2% to 1.2% or 0.25% to 1.0%.

According to various embodiments of the invention the mineral acid includes HC1 and/or H₂SO₄ and/or H₂SO₃ (e.g. as SO₂ dissolved in water) and/or H₃PO₄, and/or HNO₃. In some embodiments, the mineral acid includes H₂SO₃. In some embodiments, the mineral acid includes both H₂SO₃ and H₂SO₄. Alternatively or additionally, in some embodiments the total acid concentration in the aqueous solution contacted with the substrate at 120 is in the range of 0.1%> to 2.0%; 0.2% to 1.5%; 0.3%) to 1.2% or 0.4% to 1.0%. Alternatively or additionally, in some embodiments first liquid stream 122 includes at least 10 PPM of a marker selected from furfural, hydroxy-methyl furfural, products of furfural and hydroxy-methyl furfural condensation, organically bound sulfur, color compounds derived from sugar caramelization, levulinic acid, acetic acid, methanol, galactauronic acid and glycerol.

Alternatively or additionally, first liquid stream 122 includes xylose, mannose and glucose with a w/w ratio of [xylose + mannose] to glucose in stream 122 that is greater than 1 , greater than 2, greater than 4, greater than 6 or greater than 8 or greater than 10 and/or a w/w ratio of sugars to furfural in stream 122 that is greater than 10: 1 ; greater than 50: 1 ; greater than 100: 1 ; greater than 200: 1 or greater than 300: 1. Optionally, these embodiments employ a softwood, for example pine, as substrate 1 10.

Exemplary second liquid stream compositions

In some exemplary embodiments of the invention, second liquid stream 132 includes ash in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less than 10%) of an ash content of substrate 1 10. Alternatively or additionally, second liquid stream 132 includes calcium in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less than 10% of a calcium ion content of substrate 1 10. Alternatively or additionally, second liquid stream 132 includes divalent cations in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less than 10% of a divalent cation content of substrate 1 10. Alternatively or additionally, second liquid stream 132 includes acetate functions in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less than 10% of the acetate functions content of substrate 1 10. Alternatively or additionally, second liquid stream 132 includes methanol in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less than 10% of the methanol functions (e.g. methyl esters and/or methyl ethers) content of substrate 1 10. Alternatively or additionally, in some embodiments second liquid stream 132 includes pectin in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less than 10% of a pectin content of substrate 1 10. Alternatively or additionally, second liquid stream 132 includes lipophilic material in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less than 10% of a lipophilic material content of substrate 110. Alternatively or additionally, second liquid stream 132 includes pentose in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less than 10% of a pentose content of substrate 110. Alternatively or additionally, second liquid stream 132 includes mannose in an amount that is less than 60%; less than 50%; less than 40%; less than 30%; less than 20%; or less 5 than 10% of a mannose content of substrate 110.

Exemplary refining of sugars

In some exemplary embodiments of the invention, method 100 includes refining 140 first stream 122 and/or second stream 132. In some embodiments of the invention, method 100 includes refining both first liquid stream 122 and second liquid stream 132. Some exemplary embodiments of 10 method 100 include combining 138 at least a portion of the first soluble sugars (of stream 122) with at least a portion of the second soluble sugars (of stream 132) prior to conclusion of refining 140.

In some embodiments, refining 140 includes maintaining a pH of first liquid stream 122 and/or second liquid stream 132 between 3 and 9, between 3.5 and 8.8 or between 3.7 and 8.5 (inclusive) during refining 140.

15 Alternatively or additionally, in some embodiments method 100 includes exposing the sugars

(of streams 122 and/or 132) to no pH greater than 10, greater than 9.5, greater than 9.0 or greater than 8.5.

As described herein, in some embodiments refining 140 includes liming 210 (Fig. 2a and/or Fig. 2c). In some embodiments, first liquid stream 122 includes non-sugar organic matter, and

20 separated liming solid 215 includes at least 10%, at least 20%, at least 30%, at least 40%, at least 50%), at least 60%, at least 70%, at least 80% or at least 90% of the non-sugar organic matter from first stream 122. According to various exemplary embodiments of the invention the organic matter includes, for example, fatty acids and/or resin acids and/or phenolic compounds and/or furfurals and/or furfural condensation products and/or color bodies. In some embodiments, the organic matter

25 consists essentially of non-volatile organic compounds. Alternatively or additionally, in some embodiments first liquid stream 122 includes tall oils and separated liming solid 215 includes at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% of the tall oils from first liquid stream 122. In some embodiments, limed stream 212 includes non-sugar organic matter at a measurable concentration of less than 3.0% as a percentage of

30 dissolved solids. Alternatively or additionally, first liquid stream 122 includes one or more sulfur compounds, and separated liming solid 215 includes at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% of the sulfur compounds from first stream 122.

Alternatively or additionally, first liquid stream 122 includes furfurals and separated liming solid 35 215 includes at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%), at least 80% or at least 90% of the furfurals from first liquid stream 122. Alternatively or additionally, first liquid stream 122 includes phenols and separated liming solid 215 includes at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%), at least 80%> or at least 90%> of the phenols from first liquid stream 122.

Alternatively or additionally, first liquid stream 122 includes short chain lignin (i.e. 2000 Daltons or less) and separated liming solid 215 includes at least 10%>, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% of the short chain lignin from first liquid stream 122.

Exemplary products by process

Some exemplary embodiments of the invention relate to first liquid stream(s) 122 produced by various embodiments of method 100 described herein. Alternatively or additionally, some exemplary embodiments of the invention relate to second liquid stream(s) 132 produced by various embodiments of method 100 described herein. Alternatively or additionally, some exemplary embodiments of the invention relate to refined sugars 142 produced by various embodiments of method 100 described herein.

Exemplary Substrate types

According to various embodiments, substrate 110 includes one or more types of wood and/or by-products of wood processing (e.g. sawdust, shavings) and/or residual plant material from agricultural products as described herein.

In some exemplary embodiments of the invention, substrate 110 is wood. In some embodiments, the wood is hardwood. In other exemplary embodiments of the invention, the wood is softwood. In some exemplary embodiments of the invention, substrate 110 includes hardwood and softwood. Alternatively or additionally, in some embodiments the wood is debarked and/or chipped. Alternatively or additionally, in some embodiments substrate 110 is not contacted with a base prior to extracting 120. Alternatively or additionally, in some embodiments substrate 110 is not contacted with an acid prior to extracting 120. Alternatively or additionally, in some embodiments substrate 110 is not contacted with an organic solvent prior to extracting 120.

Exemplary advantages

In some exemplary embodiments of the invention, reducing an amount of acid used at extracting 130 contributes to an increase in industrial efficiency. Alternatively or additionally, in some embodiments extracting 120 reduces the mass of substrate (i.e. there is less mass in 124 than in 110). Thus, although second liquid stream 132 is corrosive, there is much less volume of corrosive material per unit of substrate 110 than if substrate 110 were to proceed directly to extracting 130 without extraction 120 in some embodiments of the invention.

In some exemplary embodiments of the invention, substrate 110 is provided in particles (e.g. 0.5 to 2 inch chips; longest dimension). In many embodiments, extracted substrate 124 retains a particulate form to a large extent. If the average size (e.g., longest dimension) of the largest 70% of particles of substrate 110 is defined as Al and the average size (e.g., longest dimension) of the largest 70% of particles of extracted substrate 124 is defined as A2, then, in some embodiments, A1/A2 is in the range 0.6 to 1.1 ; 0.7 to 1.0, or 0.8 to 0.9 or 0.9 to 1.0.

Alternatively or additionally, in some embodiments extracting 130 additional sugars includes contacting with a concentrated solution of a strong acid and the residence time at 130 is at least 10%> shorter compared with a contacting time required to reach a similar given sugars extraction yield in a method not including extracting 120 but otherwise conducted under the same conditions on a same substrate 110. In some embodiments, extracting 120 contributes to a reduction in time of extracting 130 (i.e. extracting 130 from extracted substrate 124 is "easier" than extracting 130 from a non- extracted substrate 110). According to various exemplary embodiments of the invention this reduction in time for extracting 130 is at least 10%>, at least 20%> at least 30%>, or at least 40%>. This comparison is made under similar (+/- 1%>) conditions of temperature and phases, optionally at a laboratory scale. "Yield" in this context indicates total extraction compared with a theoretical yield as determined by the content of water-insoluble polysaccharides in substrate 110. Alternatively or additionally, method 100 with extracting 120 generates a reduced level of furfurals (e.g., at least 10%>, 15%, 20%, 25% less furfurals) compared with furfurals generation associated with a similar given sugars extraction yield when 130 is conducted at the same conditions in a method not including extracting 120. Alternatively or additionally, method 100 with extracting 120 reduces the amount of methanol formed in extracting 130 (e.g., by at least 10%, 15%, 20%, or 25%) as compared with the amount of methanol formed with a similar given sugars extraction yield when 130 is conducted at the same conditions in a method not including not including extracting 120. Alternatively or additionally, a method 100 with extracting 120 which employs HC1 at extracting 130, produces methyl chloride by at least 10%, 15%, 20%, or 25% as compared with the amount of methyl chloride produced with a similar given sugars extraction yield in a method not including extracting 120.

In those embodiments of the invention which employ HC1 at 130, the acid concentration is

37%; 39%; 41%; 43% or 45% or intermediate or greater percentages. Alternatively or additionally, n those embodiments of the invention which employ HC1 at 130 the temperature during extraction 130 is between 4 °C and 22 °C.

According to various exemplary embodiments of the invention monitoring one or more of the above advantages at a laboratory scale provides guidance for scale-up of method 100. Thus, the described advantages comprise calibration instructions for extracting 120 in some embodiments of the invention. Such calibration considerations can be important, for example, if the composition of substrate 110 changes (e.g. due to variations in input material over time or as a result of a management decision to alter the nature of substrate 110). Any of the methods herein are designed to perform in large scale. For example, 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100 metric tons/hour of substrate 110/hour are processed according to various embodiments. Alternatively or additionally there is substantially no re-oligomerization of sugars during evaporation 284 and/or during contacting 290 and/or during removal 295 and/or during polishing 298.

In some embodiments, the refined hemicellulose sugars stream (299) contains 90%, 95%, 97%o, 99%o or substantially 100% monomeric sugars as a percentage of total sugars.

In some exemplary embodiments of the invention, extraction 130 is conducted under conditions which produce a sugar stream 132 that is corrosive to stainless steel. Corrosive stream 132 must be handled with corrosion resistant equipment and such corrosion resistant equipment contributes to increased cost of refined sugars 142. In some exemplary embodiments of the invention, performance of extraction 120 contributes to a reduction in residence time at extraction 130 and/or to a reduction in size of corrosion resistant reaction vessels employed at extracting 130. In some embodiments, reductions in residence time at 130 and/or reductions in size of corrosion resistant reaction vessels at 130 contributes to a reduction in capital costs and/or to a reduction in unit price of refined sugars 142. Alternatively or additionally, conditions at 130 which produce a sugar stream 132 that is corrosive to stainless steel rapidly degrade some hemicellulose sugars, so that extraction 120 of hemicellulose sugars (first liquid stream 122) contributes to an increase in overall yield and/or contributes to a reduction in formation of degradation products that are potentially toxic to fermenting organisms grown in a culture medium including refined sugars 142.

Alternatively or additionally, in some embodiments of the invention, method 100 produces a high yield of sugars (e.g. 95% or more); while maintaining a low degradation rate of sugars (e.g. 5% or less).

Exemplary features of extracted substrate

In some exemplary embodiments, substrate 110 includes ash and extracted substrate 124 includes less than 60%>; less than 50%; less than 40%; less than 30%; less than 20% or less than 10% of the ash content of substrate 110. Alternatively or additionally, substrate 110 includes pentose(s) and extracted substrate 124 includes less than 60%; less than 50%; less than 40%; less than 30%; less than 20%) or less than 10% of the pentose content of substrate 110. Alternatively or additionally, substrate 110 includes mannose and extracted substrate 124 includes less than 60%; less than 50%; less than 40%; less than 30%; less than 20% or less than 10% of the mannose content of substrate 110. Alternatively or additionally, substrate 110 includes calcium ions and extracted substrate 124 includes less than 60%; less than 50%; less than 40%; less than 30%; less than 20% or less than 10% of the calcium ion content of substrate 110. Alternatively or additionally, substrate 110 includes divalent cations and extracted substrate 124 includes less than 60%; less than 50%; less than 40%; less than 30%; less than 20% or less than 10% of the divalent cation content of substrate 110. Alternatively or additionally, substrate 110 includes acetate functions and extracted substrate 124 includes less than 60%; less than 50%; less than 40%; less than 30%; less than 20% or less than 10% of the acetate functions of substrate 110. In some exemplary embodiments, substrate 110 includes pectin and extracted substrate 124 includes less than 60%; less than 50%; less than 40%; less than 30%>; less than 20%> or less than 10%> of the pectin content of substrate 110. In some exemplary embodiments, substrate 110 includes lipophilic material (e.g. tall oils) and extracted substrate 124 includes less than 60%>; less than 50%; less than 40%; less than 30%; less than 20% or less than 10% of the lipophilic material content of substrate 110. In some embodiments, the lipohilic material is soluble in dichloromethane (DCM).

Alternatively or additionally, in some embodiments a pentose content of extracted substrate 124 is less than 20%; less than 15%; less than 10%; less than 5%; less than 3% or substantially 0%.

Alternatively or additionally, in some embodiments extracted substrate 124 includes cellulose and lignin and has at least two, at least three, at least four, at least five or at least six features from the following list (all features expressed on a dry matter basis):

(i) less than 5000 PPM lipophilic material;

(ii) less than 5000 PPM ash;

(iii) less than 2000 PPM Calcium (Ca);

(iv) less than 10,000 PPM pectin;

(v) less than 2000 PPM furfural; and

(vi) at least 10 PPM of a marker selected from furfural, hydroxy-methyl furfural, products of furfural and hydroxy-methyl furfural condensation, organically bound sulfur, color compounds derived from sugar caramelization, levulinic acid, acetic acid, methanol, galactauronic acid, glycerol and a water soluble solvent. In some exemplary embodiments of the invention, at least 5, 10 15 or 20 metric tons of extracted substrate 124 are produced per hour.

According to various exemplary embodiments of the invention extracted substrate 124 has three, four, five, six or even all seven of the characteristics in the list.

According to various exemplary embodiments of the invention monitoring one or more of these features of extracted substrate 124 at a laboratory scale provides guidance for scale-up of method 100. Thus, the described features of extracted substrate 124 optionally serve as calibration guidelines for extracting 120 in some embodiments of the invention. Such calibration considerations can be important, for example, if the composition of substrate 110 changes (e.g. due to variations in input material over time or as a result of a management decision to alter the nature of substrate 110).

In some embodiments, samples of substrate 110 and/or extracted substrate 124 are analyzed periodically to facilitate calibration.

Exemplary features of limed stream

In some exemplary embodiments of the invention, limed stream 212 includes less than 3.0%; less than 2.5% or less than 2.2% non-sugar organic matter.

Alternatively or additionally, in some embodiments limed stream 212 includes less than 1.0%; less than 0.5%; less than 0.25% or less than 0.1% fatty acids as a % of total dissolved solids. Alternatively or additionally, in some embodiments limed stream 212 includes less than 1.0%; less than 0.5%; less than 0.25% or less than 0.1% resin acids as a % of total dissolved solids.

Alternatively or additionally, in some embodiments limed stream 212 includes less than 0.25%; less than 0.15% or less than 0.1% furfural.

Alternatively or additionally, in some embodiments limed stream 212 includes less than 0.25%; less than 0.15% or less than 0.1% phenolic compounds.

Alternatively or additionally, in some embodiments sugars concentration in limed stream 212 is between 1% and 10%, between 2% and 8% or between 3% and 6%. In some embodiments, 70%, 80%), 90%), 95%), 97%) or 99% or intermediate or greater percentages of these sugars are present as monomeric sugars.

Exemplary features of solvent-comprising refined stream

In some exemplary embodiments of the invention, refining aqueous stream 286 includes ash and the ash content of solvent-comprising refined stream 292 is up to 60%, up to 50%, up to 40%, up to 30%), up to 20%) or up to 10%, of the ash content of the refining aqueous stream.

Exemplary optional precipitate treatment

Fig. 6a is a simplified flow scheme depicting an optional precipitate treatment method indicated generally as 600. In some exemplary embodiments, precipitate 610 includes precipitate 293. In the depicted exemplary embodiment, separated precipitate 610 including a salt of one or more organic acids is contacted 620 with a solution of a mineral acid. Optionally, the mineral acid is sulfuric acid.

In some embodiments, precipitate 610 is washed with water to form an aqueous solution including a salt of a carboxylic acid. In some embodiments, method 600 includes acidulating the aqueous solution including a salt of a carboxylic acid on a cation exchanger.

In some embodiments, precipitate 610 includes calcium salts of at least one organic acid. In some instances, contacting 620 forms gypsum and a solution of the organic acid. In some embodiments, method 600 includes separation (not depicted) of gypsum from the solution of the organic acid. In some embodiments, the separated solution of organic acid is treated in an anaerobic treatment and/or separated gypsum is washed with water.

Additional exemplary method

Fig. 7 is simplified flow scheme illustrating lignocellulose processing methods according to embodiments herein. Method 101 is similar to method 100 in many respects. Depicted exemplary method 101 includes extracting 120 a lignocellulosic substrate 110 with an aqueous solution to form a first liquid stream 122 including first soluble sugars (e.g. hemicellulose sugars) and impurities and an extracted substrate 124. Depicted exemplary method 101 includes separating 121 first liquid stream 122 from extracted substrate 124 and hydro lyzing 131 extracted substrate 124 with HC1 to form a second liquid stream 132 including second soluble sugars. Hydrolyzing 131 is an exemplary embodiment of extracting 130 (see Fig. 1) as indicated by the dashed rectangle. Depicted exemplary method includes refining 140a first liquid stream 122 to form refined hemicellulose sugars 142a and refining 140b second liquid stream 132 to form refined cellulose sugars 142b.

In some embodiments, method 101 includes combining 710 at least a portion of hemicellulose sugars 142a with at least a portion of cellulose sugars 142b. According to various exemplary embodiments of the invention refining 140a and/or 140b options and/or extraction 120 and/or 130 (131) are as described herein.

Exemplary features of de-solventized refined stream

In some exemplary embodiments of the invention, de-solventized refined stream 296 has a conductivity of less than 3000, less than 2500, less than 2000, less than 1500 or less than 1000 micro- Siemens.

Exemplary features of refined hemicellulose sugars stream

In some exemplary embodiments of the invention, refined hemicellulose sugars stream 299 includes non-sugar organic matter (e.g. less than 10%; less than 5%; less than 3%; less than 2%; less than 1%; less than 0.5%; or less than 0.1% non-sugar organic matter as a percentage of dissolved solids).

Alternatively or additionally, refined hemicellulose sugars stream 299 includes less than 0.25%; less than 0.15%; or less than 0.1% fatty acids.

Alternatively or additionally, in some embodiments refined hemicellulose sugars stream 299 includes less than 1%; less than 0.5%; less than 0.25% or less than 0.1% resin acids.

Alternatively or additionally, in some embodiments refined hemicellulose sugars stream 299 includes less than 1%; less than 0.8%; less than 0.6% or less than 0.4% furfural.

Alternatively or additionally, in some embodiments refined hemicellulose sugars stream 299 includes less than 0.5%; less than 0.3%; less than 0.2% or less than 0.1% phenolic compounds.

Alternatively or additionally, in some embodiments refined hemicellulose sugars stream 299 includes less than 0.5%; less than 0.3%; less than 0.2% or less than 0.1% water-soluble solvent.

Alternatively or additionally, in some embodiments refined hemicellulose sugars stream 299 includes less than 1.0%; less than 0.5%; less than 0.25% or less than 0.1% volatile organic matter.

Alternatively or additionally, in some embodiments refined hemicellulose sugars stream 299 has a conductivity of less than 100, less than 80, less than 60, less than 40, less than 20 or less than 10 micro-siemens.

Alternatively or additionally, in some embodiments refined hemicellulose sugars stream 299 has a sugars concentration between 20% and 70%, between 30% and 60% or between 40% and 50%.

In the description of refined hemicellulose sugars stream 299, percentages indicate a measurable amount below the indicated percentages. Alternatively or additionally, in some embodiments during refining 145 first liquid stream 122 to form refined hemicellulose sugars 299 the pH of the sugar solution is maintained between 3 and 9, between 3.5 and 8.8 or between 3.7 and 8.5.

Alternatively or additionally, in some embodiments during refining 145 first liquid stream 122 to form refined hemicellulose sugars 299 the highest pH the sugars are exposed to is 10, 9.5, 9.0 or 8.5.

Exemplary processing of refined sugars to a conversion product

In some exemplary embodiments of the invention, method 100 includes processing 150 refined sugars 142 to produce a conversion product 152. According to various exemplary embodiments of the invention processing 150 includes a biological process (e.g. fermentation) and/or an enzymatic process (e.g. application of purified enzymes and/or cell extracts and/or genetically modified microorganisms to refined sugars 142) and/or a chemical process. According to various exemplary embodiments of the invention processing 150 includes a single process, or two or more, optionally three or more processes performed in sequence so that there may be one or more intermediate products (not diagrammed). According to various exemplary embodiments of the invention conversion product(s) 152 include(s) fuels and/or carboxylic acids and/or amino acids and/or proteins and/or monomers for the polymer industry and/or acrylic acid-based product. Acrylic acid-based products include, but are not limited to diapers, various plastics, coatings, adhesives, elastomers, as well as floor polishes, and paints. In other exemplary embodiments of the invention, conversion product(s) 152 include(s) detergents and/or surfactants.

Exemplary optional variations

Referring again to Fig. 1 ; in some exemplary embodiments of the invention, method 100 includes extracting one or more additional times to produce one or more additional liquid streams (not depicted). In other exemplary embodiments of the invention, method 100 includes only extractions 120 and 130 as depicted.

Another additional exemplary method

Fig. 6b is a simplified flow diagram of a method for pelletizing extracted substrate indicated generally as 601. Depicted exemplary method 601 includes pelletizing 630 extracted substrate 124 (See Fig. 1). In some exemplary embodiments of the invention, extracted substrate 124 is produced by extracting 120 a lignocellulosic substrate 110 with an aqueous solution to form a first liquid stream 122 including hemicellulose sugars and impurities and an extracted substrate 124 and separating first liquid stream 122 from extracted substrate 124. In some embodiments, pelletizing includes reducing an average particle size and/or drying of extracted substrate 124. According to various exemplary embodiments of the invention reducing an average particle size of extracted substrate 124 includes chopping and/or grinding and/or milling and/or comminution. In some embodiments, pelletized extracted substrate 124 serves as a combustible fuel. Exemplary advantages

Referring again to Fig. 1, in some embodiments extraction 130 includes acid hydrolysis of cellulose to produce cellulose sugars (primarily glucose) in second liquid stream 132. According to some of these embodiments extraction 120 is calibrated so that first liquid stream 122 contains 5 primarily hemicellulose sugars. In some exemplary embodiments of the invention, implementation of extraction 120 contributes to an ability to apply more extreme conditions of acid hydrolysis at extraction 130. Alternatively or additionally, in some embodiments implementation of extraction 120 contributes to a shorter reaction time at extraction 130 (e.g. by allowing application of more extreme conditions). In some exemplary embodiments of the invention, sequential performance of extractions 10 120 and 130 contributes to a reduction in production of furfurals per unit of sugar(s) produced in

liquid streams 122 and/or 132.

Exemplary compositions

Some exemplary embodiments of the invention relate to a composition including (on a dry matter basis) at least 30% xylose; at least 50% hemicellulose sugars; calcium hydroxide at at least

15 70%) of saturation concentration of lime at room temperature and atmospheric pressure; and less than 3%) DCM soluble matter and/or less than 3% non sugar organic matter. In some embodiments, the composition is provided as a solution of at least 5% total dissolved solids (TDS). Optionally, such compositions are present as stream 212. In some embodiments, such a composition has a conductivity of less than 3000 micro-siemens and/or includes 0.002 to 0.2 %w/w acetic acid.

20 Other exemplary embodiments of the invention relate to a composition including at least 85% xylose and at least IPPM lime and/or at least IPPM water soluble organic solvent (e.g. acetone and/or methanol and/or ethanol).

Other exemplary embodiments of the invention relate to a composition including (on a dry matter basis) at least 80% lime (e.g. calcium oxide and/or calcium hydroxide and/or calcium

25 carbonate); and at least 10 PPM xylose. Optionally, such a composition includes at least IPPM of a solvent selected from the group consisting of methanol, ethanol and acetone. In some embodiments, the composition includes at least 1 PPM acetone. Alternatively or additionally, in some embodiments, the composition includes at least 1 PPM of one or more tall oils. Alternatively or additionally, in some embodiments, the composition includes at least 1 PPM of one or more furfurals. Alternatively or

30 additionally, in some embodiments, the composition includes at least 1 PPM short chain lignin (i.e. less than 2000 Daltons). Such a composition may exist, for example, as liming solid 215.

It is expected that during the life of this patent many refining 140 and processing 150 techniques will be developed and the scope of the invention is intended to include all such new technologies a priori.

35 Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

Specifically, a variety of numerical indicators have been utilized. It should be understood that these numerical indicators could vary even further based upon a variety of engineering principles, materials, intended use and designs incorporated into the various embodiments of the invention. Additionally, components and/or actions ascribed to exemplary embodiments of the invention and depicted as a single unit may be divided into subunits. Conversely, components and/or actions ascribed to exemplary embodiments of the invention and depicted as sub-units/individual actions may be combined into a single unit/action with the described/depicted function.

Alternatively, or additionally, features used to describe a method can be used to characterize an apparatus and features used to describe an apparatus can be used to characterize a method.

It should be further understood that the individual features described herein can be combined in all possible combinations and sub-combinations to produce additional embodiments of the invention. The examples given above are exemplary in nature and are not intended to limit the scope of the invention which is defined solely by the following claims.

Each recitation of an embodiment of the invention that includes a specific feature, part, component, module or process is an explicit statement that additional embodiments not including the recited feature, part, component, module or process exist.

All publications, references, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

WHAT IS CLAIMED IS:

1. A method comprising:

(a) extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream comprising hemicellulose sugars and impurities and an extracted substrate;

(b) separating said first liquid stream from said extracted substrate; and

(c) refining said first liquid stream to form a refined hemicellulose sugars stream;

wherein said refining comprises at least one of:

(i) liming to form a limed stream; and

(ii) concentrating sugars in said first liquid stream to at least 40% and contacting with a water-soluble solvent to form a solvent-comprising refined stream.

2. A method according to claim 1, wherein said water-soluble solvent comprises at least one member of the group consisting of acetone, methanol and ethanol.

3. A method according to claim 1, wherein said refining comprises both said liming and said contacting with a water-soluble solvent.

4. A method according to any one of claims 1 to 3, comprising conducting said liming under conditions which form a slurry.

5. A method according to claim 1, wherein said refining comprises:

contacting a refining aqueous stream comprising sugars and impurities with a water-soluble solvent, to produce a solvent-comprising refined stream and a precipitate; and

separating said solvent-comprising refined stream from said precipitate.

6. A method according to claim 5, comprising:

removing solvent from said solvent-comprising refined stream to generate a de-solventized refined stream.

7. A method according to any one of claims 1 to 3, wherein said refining comprises polishing of said de-solventized refined stream to form a refined hemicellulose sugars stream.

8. A method according to claim 1, wherein said liming comprises contacting with C02.

9. A method according to claim 1 or 8, wherein said liming comprises separating solid from a slurry to form separated liming solid, and a limed stream comprising sugars.

10. A method according to any one of claims 1 to 3, comprising crystallizing xylose from at least one stream derived from said first liquid stream and separating the crystalline xylose from a mother liquor.

11. A method according to any one of claims 1 to 3, comprising chromatographically separating said first liquid stream to form a xylose enriched fraction.

12. A method according to claim 10, comprising chromatographically separating said at least one stream derived from said first liquid stream to form a xylose enriched fraction.

13. A method according to claim 10, comprising chromatographically treating said mother liquor to form a second xylose enriched fraction and a second xylose- depleted fraction.

14. A method according to claim 13, comprising recycling said second xylose enriched fraction to said crystallizing.

15. A method according to any one of claims 1 to 3, comprising maintaining the pH of said first liquid stream between 3 and 9 during said refining.

16. A method according to any one of claims 1 to 3, comprising exposing the sugars to no pH greater than 10.

17. A method according to claim 9, wherein said first liquid stream comprises non-sugar organic matter, and wherein said separated liming solid comprise at least 10% of said non-sugar organic matter of said first liquid stream.

18. A method according to claim 9, wherein said first liquid stream comprises tall oils, and wherein said separated liming solid comprise at least 10%> of said tall oils in said first liquid stream.

19. A method according to any of claims 9, 17 or 18, comprising:

contacting said separated liming solid with an acid to form an organic phase; and

separating said organic phase.

20. A method according to any one of claims 1 to 3, wherein said refining comprises liming to form a limed stream and said method comprises evaporating said limed stream to form a refining aqueous stream and vapor condensate.

21. A method according to claim 20 comprising:

(i) contacting said refining aqueous stream with a water-soluble solvent, wherein said contacting results in a solvent-comprising refined stream and a precipitate,

(ii) separating said solvent-comprising refined stream from said precipitate,

(iii) removing solvent from said solvent-comprising refined stream to generate de-solventized refined stream; and

(iv) polishing of said de-solventized refined stream to form a refined hemicellulose sugars stream.

22. A method according to any one of claims 1 to 3, comprising:

extracting additional sugars from said extracted substrate to form a second liquid stream comprising additional sugars, said second liquid stream being corrosive to stainless steel at the conditions of the extracting additional sugars; and

refining said second liquid stream to produce a refined glucose stream.

23. A method according to claim 22, comprising:

combining at least a fraction of one or more streams selected from the group consisting of said limed stream, said refining aqueous stream, said solvent-comprising refined stream, a de- solventized refined stream and said refined hemicellulose sugars stream with at least a fraction of said refined glucose stream during refining of said second liquid stream to form a partially refined sugar mixture.

24. A method according to claim 23 comprising refining said partially refined sugar mixture to form a refined sugar mixture.

25. A method according to any one of claims 1 to 3, wherein said limed stream comprises less than 3.0% non-sugar organic matter as a percentage of dissolved solids.

26. A method according to claim 5, wherein said refining aqueous stream comprises ash and wherein the ash content of said solvent-comprising refined stream is less than 60%> of the ash content of said refining aqueous stream.

27. A method according to claim 5, comprising contacting said separated precipitate with a solution of a mineral acid ; wherein said separated precipitate comprises a salt of an organic acid .

28. A method according to claim 6, wherein said de-solventized refined stream has a conductivity of less than 3000 micro-siemens.

29. A method according to claim 7, wherein said refined hemicellulose sugars stream comprises less than 10% non-sugar organic matter as a percentage of dissolved solids.

30. A method according to any one of claims 1 to 3, wherein said first liquid stream, said refining aqueous stream or both contain less than 5% of lignin in said lignocellulosic substrate.

31. A method according to any one of claims 1 to 3 or claim 27, wherein said lignocellulosic substrate is hardwood.

32. A method according to any one of claims 1 to 3, wherein said first liquid stream comprises at least 40% of the hemicellulose sugars of said lignocellulosic substrate.

33. A method according to any one of claims 1 to 3, wherein a sugars concentration in said first liquid stream is between 1% and 10%>.

34. A method according to claim 1, wherein at least 50%> of the sugars in said first liquid stream are in monosaccharide form.

35. A method according to any one of claims 1 to 3, wherein the purity of sugars in said first liquid stream is greater than 40%>.

36. A method according to any one of claims 1 to 3, wherein the purity of sugars in said first liquid stream is less than 70%.

37. A method according to any one of claims 1 to 3, wherein said first liquid stream comprises at least 30%) of an ash content of said substrate.

38. A method according to any one of claims 1 to 3, wherein said first liquid stream comprises xylose and mannose and glucose and wherein:

(i) the w/w ratio of xylose + mannose to glucose is greater than 1.0; and (ii) the w/w ratio of sugars to furfural w/w is greater than 10:1.

39. A method according to any one of claims 1 to 3, wherein said first liquid stream comprises acetic acid at a concentration of 0.002 to 0.2 %w/w.

40. A method according to any one of claims 1 to 3, wherein said first liquid stream comprises xylose.

41. A method according to claim 40, wherein at least 35% of the sugars in said first liquid stream are xylose on a weight basis.

42. A method according to any one of claims 1 to 3, comprising pulping said extracted substrate.

43. A method according to any one of claims 1 to 3, wherein said extracting comprises maintaining at a temperature between 100°C and 160°C.

44. A method according to claim 43, wherein said extracting is conducted at a pressure greater than 1 atmosphere.

45. A method according to claim 43 or claim 44, wherein said solution comprises a mineral acid.

46. A method according to any one of claims 1 to 3, comprising pelletizing said extracted substrate.

47. A method comprising:

(a) extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream comprising first soluble sugars and impurities and an extracted substrate;

(b) separating said first liquid stream from said extracted substrate; and

(c) extracting additional sugars from the extracted substrate to form a second liquid stream comprising second soluble sugars, said second liquid stream being corrosive to stainless steel at the conditions of the extracting additional sugars.

48. A method according to claim 47, comprising:

(d) refining at least one of said first liquid stream and said second liquid stream to form refined sugars.

49. A method according to claim 47, wherein said extracting a substrate comprises maintaining under pressure at a temperature between 100°C and 160°C.

50. A method according to claim 47, wherein said extracting a substrate comprises contacting with an aqueous acid solution comprising H₂SO₃.

51. A method according to claim 50, wherein said aqueous acid solution comprises H₂SO₃ and

52. A method according to any one of claims 47 to 51, wherein said extracting additional sugars comprises contacting with an aqueous hydrolyzing solution of an acid.

53. A method according to any one of claims 47 to 51, wherein said extracting additional sugars comprises contacting with an aqueous hydrolyzing solution comprising at least 30% wt. sulfuric acid.

54. A method according to claim 52, wherein the ratio of acid to substrate in said hydrolyzing solution is smaller by at least 10% compared with the amount of acid required to reach a similar given sugars extraction yield when (c) is conducted at the same conditions in a method not including (a) and (b).

55. A method according to any one of claims 47 to 51, wherein the total yield of sugars in said first and second liquid streams corresponds to at least 90% of a theoretical yield.

56. A method according to any one of claims 47 to 51, wherein said extracting additional sugars comprises contacting with a reactive fluid.

57. A method according to any one of claims 47 to 51, wherein said extracting additional sugars comprises contacting at supercritical temperature, critical temperature or at near-critical temperature with an aqueous solution comprising an acid having pKa <4.

58. A method according to any one of claims 47 to 51, wherein said first liquid stream comprises at least 40% of the hemicellulose sugars of said lignocellulosic substrate.

59. A method according to any one of claims 47 to 51, wherein the sugars in the first liquid stream comprise at least 20% of total extracted pentoses.

60. A method according to any one of claims 47 to 51, wherein at least 50% of the sugars in said first liquid stream are in monosaccharide form.

61. A method according to any one of claims 47 to 51, wherein the purity of sugars in said first liquid stream is greater than 40%>.

62. A method according to any one of claims 47 to 51, wherein the purity of sugars in said first liquid stream is less than 70%.

63. A method according to any one of claims 47 to 51, wherein said first liquid stream comprises at least 30% of the ash content of said lignocellulosic substrate.

64. A method according to any one of claims 47 to 51, wherein said first liquid stream comprises acetic acid at a concentration of 0.002 to 0.2 %w/w.

65. A method according to any one of claims 47 to 51, wherein said first liquid stream comprises xylose, mannose and glucose and wherein:

(i) the w/w ratio of xylose + mannose to glucose in said first liquid stream is greater than 1.0; and

(ii) the w/w ratio of sugars to furfurals in said first liquid stream is greater than

10:1.

66. A method according to any one of claims 47 to 51, wherein said second liquid stream comprises less than 60% of an ash content of said lignocellulosic substrate.

67. A method according to claim 48, comprising refining both said first liquid stream and said second liquid stream.

68. A method according to claim 67, comprising combining at least a portion of said first soluble sugars with at least a portion of said second soluble sugars prior to conclusion of said refining.

69. A first liquid stream produced by a method according to any of claims 47, or 49 to 66.

70. A second liquid stream produced by a method according to any of claims 47, or 49 to 66.

71. Refined sugars produced by a method according to any one of claims 48 or 67.

72. A method according to any one of claims 47 to 51, wherein said lignocellulosic substrate is not contacted with a base prior to said extracting.

73. A method according to any one of claims 47 to 51, wherein said lignocellulosic substrate is not contacted with an acid prior to said extracting.

74. A method according to any one of claims 47 to 51, wherein said lignocellulosic substrate is not contacted with an organic solvent prior to said extracting.

75. A method according to any one of claims 47 to 51, wherein said lignocellulosic substrate is provided in particles, wherein the average size of 70% of said substrate particles is Al , wherein the average size of 70% of the said extracted substrate particles is A2 and wherein A1/A2 is in the range between 0.6 and 1.1.

76. A method according to any one of claims 47 to 51, wherein said extracting additional sugars comprises contacting with a concentrated solution of a strong acid, characterized by a contacting time that is at least 10%> shorter compared with the contacting time required to reach a similar given sugars extraction yield when (c) is conducted at the same conditions in a method not including (a) and (b).

77. A method according to any one of claims 47 to 51, characterized by generation of furfurals that is at least 10%> smaller compared with furfurals generation associated with a similar given sugars extraction yield when (c) is conducted at the same conditions in a method not including (a) and (b).

78. A method according to any one of claims 47 to 51, wherein the amount of methanol formed in said extracting additional sugars is smaller by at least 10%> compared with the amount of methanol formed with a similar given sugars extraction yield when (c) is conducted at the same conditions in a method not including (a) and (b).

79. A method according to any one of claims 47 to 51, wherein said extracted substrate comprises less than 60%> of an ash content of said lignocellulosic substrate.

80. A method according to any one of claims 47 to 51, wherein the pentose content of said extracted substrate is less than 20%>.

81. A method according to any one of claims 47 to 51 , wherein said extracting a lignocellulosic substrate comprises applying a predetermined pressure-temperature-time profile to said substrate.

82. A method according to claim 81, wherein said predetermined pressure-temperature-time profile comprises steam explosion.

83. A method according to claim 81, wherein said predetermined pressure-temperature-time profile is characterized by severity factor of at least 3.

84. A method according to claim 81, wherein said predetermined pressure-temperature-time profile is characterized by severity factor of less than 5.

85. A method according to claim 81, wherein said predetermined pressure-temperature-time profile is characterized by severity factor in the range of 3.4 to 4.2.

86. A method according to any one of claims 47 to 51, wherein said extracting a lignocellulosic substrate comprises applying a predetermined pressure-temperature-time profile and contacting with at least one of a volatile acid and a dilute acid solution and said contacting is conducted prior to said applying.

87. A method according to any one of claims 47 to 51, wherein said extracting a lignocellulosic substrate comprises applying a predetermined pressure-temperature-time profile and contacting with an aqueous solution and said contacting is conducted subsequent to said applying.

88. A method according to any one of claims 47 to 51, wherein said extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream comprises applying a predetermined pressure-temperature-time profile and contacting with a water-soluble solvent and wherein said contacting is conducted prior to said applying.

89. A method according to any one of claims 47 to 51, wherein said extracting a lignocellulosic substrate with an aqueous solution to form a first liquid stream comprises applying a predetermined pressure-temperature-time profile and contacting with a water-soluble solvent and wherein said contacting is conducted subsequent to said applying.

90. A method comprising:

(a) extracting a lignocellulosic substrate to form a first liquid stream comprising first soluble sugars and impurities and an extracted substrate;

(b) separating said first liquid stream from said extracted substrate; and

(c) hydrolyzing said extracted substrate with HC1 to form a second liquid stream comprising second soluble sugars,

(d) refining said first liquid stream to form refined hemicellulose sugars;

(e) refining said second liquid stream to form refined cellulose sugars.

91. A method according to claim 90, comprising combining at least a portion of said first soluble sugars with at least a portion of said second soluble sugars.

92. A composition comprising (on a dry matter basis):

(a) at least 30% xylose;

(b) at least 50% hemicellulose sugars;

(c) Ca hydroxide at at least 70% of saturation concentration of lime at room temperature and atmospheric pressure; and

(d) less than 3% DCM soluble matter.

93. A composition comprising (on a dry matter basis):

(a) at least 30% xylose;

(b) at least 50% hemicellulose sugars;

(d) less than 3% non sugar organic matter.

94. A composition according to claim 92 or claim 93, provided as a solution of at least 5% total dissolved solids (TDS).

95. A composition according to claim 92 or claim 93, having a conductivity of less than 3000 micro-siemens.

96. A composition according to any of claims 92 to 95, comprising 0.002 to 0.2 %w/w acetic acid.

97. A composition comprising (on a dry matter basis):

at least 85% xylose; and

at least 1PPM lime.

98. A composition comprising (on a dry matter basis):

at least 85% xylose; and

at least 1PPM water soluble solvent.

99. A composition comprising (on a dry matter basis):

at least 80% lime; and

at least 10 PPM xylose.

100. A composition according to claim 99, comprising at least 1PPM of a solvent selected from the group consisting of methanol, ethanol and acetone.

101. A composition according to claim 100, comprising at least 1PPM acetone.

102. A method comprising:

(a) extracting a lignocellulosic substrate to form a first liquid stream comprising at least 90%) of hemicellulose sugars and less than 10%> of cellulose (as soluble sugars) in the substrate and an extracted substrate;

(b) hydrolyzing the extracted substrate to produce a second liquid stream containing at least 90%) of residual cellulose in the extracted substrate as soluble sugars; and

(c) refining sugars from each of the first liquid stream and the second liquid stream; wherein the amount of hemicellulose sugars and cellulose sugars isolated from the lignocellulosic substrate is greater than 95% of the theoretical yield for the lignocellulosic substrate.

103. A method according to claim 102, wherein the extracting to form a first liquid stream comprises maintaining the lignocellulosic substrate under pressure, at elevated temperature and in contact with an acid at a concentration up to 2%>.

104. A method according to claim 102, wherein the lignocellulosic substrate is pine.

105. A method according to any one of claims 101 to 104, wherein the hydrolyzing comprises contacting the extracted substrate with an acid at a concentration greater than 30%> at ambient temperature and pressure.