SK16932001A3 - Utilization of self-emulsifying oils in fermentation processes - Google Patents

Abstract

The invention relates to the utilization of self-emulsifying oils selected from the group consisting of ethoxylated triglycerides of vegetable origin in fermentation processes.

Description

Technical field

The present invention relates to the use of self-emulsifying oils in a fermentation process.

BACKGROUND OF THE INVENTION

Microbiological processes are increasingly used in the synthesis of complex natural substances or other organic compounds, such as antibiotics. This is a matter of metabolism under anaerobic or aerobic conditions, in which microorganisms, in particular bacteria or fungi, are involved. For such processes, various, not always mutually limited terms such as "bioconversion", "biotransformation" or "fermentation" are used in the scientific world. The latter term is also used in the present application for processes in which microorganisms, preferably bacteria, are used for the conversion or synthesis of chemical compounds.

In developing and optimizing fermentation processes, the reaction medium in which the microbiological exchange takes place is particularly important. In particular, the reaction medium, in each case an aqueous solution or dispersion, has an effect on the yield and efficiency of the process. To enable successful metabolism to the desired products, microorganisms such as nutrients need carbon, nitrogen and certain trace elements in bound form, for example calcium, iron, phosphorus or zinc. Furthermore, it is necessary to regularly maintain a certain, mostly narrow temperature range and pH. For more details, see the textbook by W. Crueger / A. Crueger, Biotechnology - Lehrbuch der angewandten Microbiology, 2nd edition 1984, R. Oldenbourg Verlag. In particular, Chapter 5 of this work deals with the basics of fermentation techniques. This part of the literature is therefore also expressly part of the publication of the present application. In addition to energy-rich sugars or derivatives thereof, natural fats or oils are also used as nutrients for microorganisms, as well as derivatives of these classes of substances, such as glycerin, glycerides, fatty acids or fatty acid esters. Of course

- The culture media must not contain any substances which could adversely affect the metabolism of the micro-organism.

For example, DE 37 38 812 A1 discloses a microbial process for the production of alpha-omega-dicarboxylic acids, wherein the bacteria of the Candida tropicalis strain convert methyl laurate into the desired dicarboxylic acids. The conversion is carried out in aqueous medium at pH 6.0 and 30 ° C. In addition to microorganisms, the medium contains, as an energy source, glucose, as an emulsifier, ethoxylated sorbitan monooleate, yeast extract, steeping water and sources of inorganic nitrogen and phosphorus. Methyl laurate is then added to the medium. The type of emulsion that is produced in a fermenter or in which methyl laurate is added to the medium is not apparent from the specification. EP 0 535 939 A1 discloses a process for the production of omega-9 multiply unsaturated fatty acids, wherein in the aqueous culture medium the desired multiply unsaturated fatty acids produce suitable microorganisms in the presence of sugar as a source of energy and inorganic or organic nitrogen sources as well as methyl esters. of fatty acids.

However, it is also known to use only fatty substances of the type mentioned above as energy sources. This is of particular interest from an economic point of view, since such fatty substances are generally cheaper than sugars, starches and the like. Park et al. (Park et al., Journal of Fermentation and Bioengineering, Vol. 82, No. 2, 183-186, 1996) disclose a fermentation process for the production of tylosin using microorganisms of the strain Streptomyces fradiae in an aqueous medium containing as the sole carbon source rapeseed oil in the starting amount of about 60g / l.

In the fermentation process, among other things, the oxygen content of the medium or of the fermentation mixture plays a decisive role. Oxygen plays a role of substrate in aerobic processes. It is critical whether oxygen can be transferred from the gaseous to the liquid phase containing the microorganisms that is sufficient for the process. An important parameter is the specific exchange surface, which is usually determined by the oxygen exchange coefficient kLa (cf. section of the Crueger literature, chapter 5, page 71 et seq.). The adjustment of the optimum oxygen supply is typically carried out by stirring the fermentation mixture, whereby oxygen or air is mixed into the liquid and thus at the boundary surface.

-3the gas is being exchanged. Naturally, significant mechanical energy input by vigorous mixing, as reported by Park et al., Can also damage part of the culture and thus reduce process yield. In addition, dead microorganisms are themselves further degraded and can cause the formation of degradation products by poisoning a culture that prevents economical production. It is known from the work of Goma and Rols (G. Goma, JL Rols, Biotech. Let., Vol. 13, No. 1, pp. 7-12, 1991) that the use of soybean oil in a fermentation process for the production of antibiotics leads to an improvement in exchange of oxygen to _La , which can lead to an increase in the yield of the whole process with the same energy input (mixing).

It is an object of the present invention to improve the fermentation process so that, on the one hand, the use of cost-effective carbon sources is possible and, on the other hand, to ensure a sufficient oxygen supply of the microorganisms without impermissible mechanical loading of the microorganisms. SUMMARY OF THE INVENTION The object is to find a method of minimizing mechanical energy input in a fermentation process without reducing the yield, more preferably to increase the yield despite reducing the energy input.

The use of self-emulsifying oils has been found to address the above task.

SUMMARY OF THE INVENTION

The present invention provides the use of self-emulsifying oils selected from the group of ethoxylated triglycerides of plant origin in a fermentation process.

The self-emulsifying compounds are substances which, when mixed with water, form stable emulsions with water without the addition of additional emulsifiers. Self-emulsifying oils are therefore added to the aqueous fermentation broth directly or in the form of aqueous emulsions. An oil-in-water emulsion is then formed in the fermentation mixture itself. The fermentation mixture contains microorganisms as well as a source of nitrogen and trace elements and optionally other auxiliaries, in particular antifoams. Possible sources of nitrogen are, for example: peptone, yeast and malt extract, steep water, urea or lecithins. The trace elements may be present in the form of inorganic salts, for example sodium or potassium nitrate, ammonium nitrate, ammonium sulfate, iron sulfate, etc. The oils emulsify without further

- energy input, so that intensified mixing of the fermentation broth is no longer necessary and the shear loading of the microorganisms is reduced, resulting in higher yields. The details of the fermentation process, in particular the rate and amount of the emulsion or oil to be metered, are based on the type of microorganisms and the fermentation process selected and can be adapted to those of skill in the art. Suitable self-emulsifying oils are natural oils of vegetable origin which have reacted with ethylene oxide in a known manner. This is essentially a mixture of triglycerides, wherein the glycerin is always completely esterified with long-chain fatty acids. Particularly suitable are vegetable oils selected from the group of peanut oil, coconut oil, linseed oil, palm oil, olive oil, palm kernel oil, castor oil, rapeseed oil, sesame oil, soybean oil and sunflower oil. Most preferred are rapeseed oil, soybean oil and sunflower oil.

Peanut oil contains on average (based on fatty acids) 54% by weight. % oleic acid, 24 wt. % linoleic acid, 1 wt. % linolenic acid, 1 wt. % arachic acid, 10 wt. palmitic acid as well as 4% stearic acid. The melting point is from 2 to 3 ° C.

Linseed oil contains mostly 5 wt. % palmitic acid, 4 wt. % stearic acid, 22 wt. % oleic acid, 17 wt. % linoleic acid and 52 wt. Linolenic acid. The iodine number ranges from 155 to 205. The saponification number is from 188 to 196 and the melting point is about -20 ° C.

The coconut oil contains from about 0.2 to 1 wt.% Of fatty acids. % hexanoic acid, from 5 to 8 wt. % octanoic acid, from 6 to 9 wt. % decanoic acid, from 45 to 51 wt. % lauric acid, from 16 to 19 wt. % myristic acid, from 9 to 11 wt. % palmitic acid, from 2 to 3 wt. % stearic acid, less than 0.5 wt. % of behenic acid, from 8 to 10% oleic acid and up to 1% by weight; Linoleic acid. The iodine number ranges from

7.5 to 9.5, saponification number from 0.88 to 0.9. The melting point is in the range of 20 to 23 ° C.

Olive oil predominantly contains oleic acid (cf. Lebensmittelchem. Gerichtl. Chem., 39, 112-114, 1985). Palm oil contains approximately 2% myristic acid, 42% palmitic acid, 5% as a fatty acid component

-5hmotn. % stearic acid, 41 wt. % oleic acid, 10 wt. Linoleic acid. Palm kernel oil typically has the following composition relative to the fatty acid spectrum: 9 wt. % caproic / caprylic / capric acid, 50 wt. % lauric acid, 15 wt. % myristic acid, 7 wt. % palmitic acid, 2 wt. % stearic acid, 15 wt. % oleic acid and 1 wt. Linoleic acid.

Rape oil typically contains about 48 wt. % erucic acid, 15 wt. % oleic acid, 14 wt. % linoleic acid, 8 wt. % linolenic acid, 5 wt. % of icosenoic acid, 3 wt. % palmitic acid, 2 wt. % hexadecenoic acid and 1 wt. docosadienoic acid. Rapeseed oil from the new variety is enriched with unsaturated proportions. Typical proportions of fatty acids are erucic acid 0.5% by weight, oleic acid 63% by weight, linoleic acid 20% by weight, linolenic acid 9% by weight, icosenic acid 1% by weight, palmitic acid 4% by weight, % hexadecenic acid 2 wt. and docosadienoic acid 1 wt.

Castor oil contains from 80 to 85 wt. % of ricinoleic acid glyceride, moreover, about 7 wt. % of oleic acid glycerides, up to 3% linoleic acid glycerides, and up to about 2% by weight; glycerides of palmitic acid and stearic acid.

Soybean oil contains from 55 to 65 wt. % of the total fatty acid content of polyunsaturated acids, in particular linoleic acid and linolenic acid. A similar situation is also in sunflower oil, the typical fatty acid spectrum of which, based on the total fatty acid content, is as follows: about 1% myristic acid, from 3 to 10% by weight of the fatty acid; % palmitic acid, from 14 to 65 wt. % oleic acid and from 20 to 75 wt. Linoleic acid.

All of the above data on the amounts of fatty acids in triglycerides are, as is known, dependent on the quality of the raw materials and can therefore fluctuate quantitatively.

The oils are alkoxylated with ethylene oxide under pressure, optionally in the presence of acidic or basic catalysts, with those ethoxylates containing from 1 to 10, preferably from 1 to 5, most preferably from 1 to 3 mol of ethylene oxide per mole of triglyceride being preferred. Particularly preferred are ethoxylates based on soybean oil, sunflower oil and / or rapeseed oil. They are particularly preferred

-6-crepe oil with 3 and / or 5 moles of ethylene oxide per mole of triglyceride as well as soybean oil, ethoxylated with 2 moles of ethylene oxide. The oils can be used in any mixture with each other or in pure form. They are used either directly or in the form of aqueous emulsions. In the latter case, the emulsions contain from 99 to 1 wt. % water and from 1 to 99 wt. self-emulsifying oils. It is preferred to use emulsions which contain from 90 to 99 wt. % of self-emulsifying oils and from 1 to 10 wt. water. It is also possible, although not preferred, to use other adjuvants, such as antifoams or emulsifiers, in addition to oils. However, it is within the skill of the art to introduce as little as possible additives into the fermentation process in the sense of the present teachings.

Self-emulsifying oils can be used in fermentation processes of all types. It is possible to use all process arrangements known to the person skilled in the art, for example in batches, semi-continuous as well as continuous fermentation. All fermentation systems known to those skilled in the art are also applicable. For details, see Crueger, pages 50 to 70. The use of microemulsions is not even limited to certain microorganisms, but emulsions can be used to produce or convert all compounds by fermentation known to those skilled in the art. In addition to conventional fermentation processes that are mainly used for the synthesis of antibiotics (cf. Crueger, pages 197 to 242), the emulsions described are also suitable for use in microbial transformation ("bioconversion"), for example for transformation of steroids and sterins, antibiotics and pesticides or vitamins (cf. Crueger, pages 254-273). However, it is preferred to use in the fermentation process for the production of antibiotics, for example chefalosporine, tylosin or erythromycin.

The use of the ethoxylated triglycerides of the invention has, for example, a beneficial effect in the production of penicillin G and cephalosporins. Compared to the use of unethoxylated soybean oil (1% by weight each), the use of ethoxylated triglycerides leads to improved emulsification of the fermentation broth and increased oxygen transfer. This makes it possible to reduce the stirring speed in the fermenter without reducing the yield.

Claims (5)

PATENT CLAIMS Use of self-emulsifying oils selected from the group of ethoxylated triglycerides of plant origin in a fermentation process. The use according to claim 1, wherein the triglycerides are of plant origin, and wherein 1 mole of the triglyceride has reacted with from 1 to 10, more preferably from 1 to 5, and most preferably from 1 to 3 moles of ethylene oxide. Use according to claim 1 or 2, wherein the self-emulsifying oils are selected from the group of ethoxylated rapeseed oil, soybean oil and / or sunflower oil. Use according to claim 1 or 2, wherein the oils are used in the form of an aqueous emulsion. Use according to claim 3, wherein emulsions containing from 99 to 1% by weight of the emulsion are used. % water and from 1 to 99 wt. of self-emulsifying oil.