CN105803002A - Method for preparing hydrogen by virtue of xylose - Google Patents

Abstract

The invention discloses a method for preparing hydrogen by using xylose, comprising: 1) taking Klebsiella oxytoca GS-4-08 strain, culturing to obtain seed liquid; 2) taking the seed liquid and inoculating it in a sterilized hydrogen production medium , and then aerobic growth at 35°C; a large amount of Klebsiella oxytoca GS-4-08 strain culture solution obtained from the cultivation; 3) Nitrogen treatment was carried out on the culture solution, and after the nitrogen aeration was completed, the aerobic growth to exponential growth The culture solution at the end stage was added to the xylose solution according to the inoculation rate of 100%; 4) Anaerobic reaction, hydrogen gas was collected. The invention utilizes microbial anaerobic fermentation of xylose to produce hydrogen, has multiple advantages such as pollution control, environmental protection, and production capacity, and has broad development prospects. A large amount of renewable lignocellulosic biomass in nature is abundant and cheap. The hydrolyzed components of lignocellulose are mainly monosaccharides, and the five-carbon sugars in monosaccharides account for about 30-40%. It is of great significance to expand the scope of substrates, reduce the cost of biohydrogen production, and realize the industrialization of biohydrogen production.

Description

A kind of method that utilizes xylose to prepare hydrogen

technical field

The invention belongs to the field of new energy, and relates to a method for preparing hydrogen from xylose.

Background technique

As an efficient, clean and renewable energy, hydrogen has attracted more and more attention. Among various hydrogen production methods, the use of microbial anaerobic fermentation of biomass (such as organic wastewater, organic waste, etc.) to produce hydrogen has multiple advantages such as pollution control, environmental protection and production capacity, and has broad development prospects. Researchers have done a lot of fruitful research work, one of which is to expand the scope of substrate utilization. A large amount of renewable lignocellulosic biomass in nature is abundant and cheap. If the key problem of using lignocellulose as a raw material to obtain hydrogen can be solved, it will make it possible to obtain cheap hydrogen and realize industrialization. Lignocellulose is mainly composed of lignin, cellulose and hemicellulose. The hydrolyzed components of cellulose and hemicellulose are mainly monosaccharides and a small amount of simple polysaccharides, of which the monosaccharides are mainly six-carbon sugars of about It accounts for 60%~70%, and the five-carbon sugar mainly composed of xylose accounts for about 30%~40%. However, there have been reports on the preparation of hydrogen from glucose, while xylose has not been applied due to problems such as difficult decomposition. Therefore, it is of great significance to study the hydrogen production characteristics of five-carbon sugars such as xylose to expand the scope of substrates, reduce the cost of biological hydrogen production, and realize the industrialization of biological hydrogen production.

Contents of the invention

Purpose of the invention: In view of the deficiencies in the prior art, the purpose of the invention is to provide a method for producing hydrogen from xylose, reduce the cost of biological hydrogen production, and realize the industrialization of biological hydrogen production.

Technical solution: In order to realize the above-mentioned purpose of the invention, the technical solution adopted in the present invention is:

A method for producing hydrogen from xylose, comprising the steps of:

1) Take the Klebsiella oxytoca GS-4-08 strain and cultivate it to obtain the seed solution;

2) Take the seed liquid and inoculate it in the sterilized bacterial growth medium, and then perform aerobic growth at 35°C; cultivate a large amount of Klebsiella oxytoca GS-4-08 strain culture liquid;

3) Nitrogen aeration is performed on the hydrogen-producing medium. After the nitrogen aeration is completed, the culture solution grown aerobically to the end of exponential growth is added to the hydrogen-producing medium at an inoculation rate of 100%;

4) Anaerobic reaction, collecting hydrogen.

In step 1), the seed liquid is incubated with the growth medium.

In step 2), the formula of the hydrogen production medium is: 0.5g/L KH ₂ PO ₄ , 1.57g/L Na ₂ HPO ₄ ·12H ₂ O, 0.1g/L MgSO ₄ ·7H ₂ O.

In step 2), the pH value of the hydrogen-producing medium is about 7.0.

In step 2), aerobic growth was carried out at 35°C for 12h.

In step 3), the concentration of xylose solution is 2-8g/L.

In step 4), the anaerobic reaction lasts for more than 48 hours.

Beneficial effects: A large amount of renewable lignocellulosic biomass in nature is abundant and cheap. Lignocellulose hydrolysis components are mainly monosaccharides, and five-carbon sugars in monosaccharides account for about 30-40%. Therefore, effective use of xylose to produce hydrogen It is of great significance to expand the scope of substrates, reduce the cost of biohydrogen production, and realize the industrialization of biohydrogen production. The invention uses Klebsiella oxytoca GS-4-08 strain to anaerobically ferment xylose to produce hydrogen, and the conversion rate is 38.5mL hydrogen/g xylose. It has multiple advantages such as pollution control, environmental protection and production capacity. It has broad development prospects and can realize industrialization .

Description of drawings

Fig. 1 is the result figure of hydrogen production under different xylose concentrations;

Fig. 2 is a result graph of total hydrogen production under 1% inoculum rate.

detailed description

The present invention will be further described below in conjunction with specific embodiments.

Example 1

A method for producing hydrogen from xylose, comprising the steps of:

1) Take the Klebsiella oxytoca GS-4-08 strain (the strain disclosed in CN105524944A), activate it with the growth medium, and obtain the seed liquid; the formula of the growth medium is: yeast extract 5g/L, peptone 10g/L, chlorine Sodium chloride 10g/L.

2) Take the seed liquid and inoculate it in the sterilized growth medium. The bacterial activation temperature is 35°C, the rotation speed is 180r/min, and the aerobic growth is performed for 12 hours; The formula is: KH ₂ PO ₄ 0.5g/L, Na ₂ HPO ₄ ·12H ₂ O 1.57 g/L, MgSO ₄ ·7H ₂ O 0.1g/L.

3) After the nitrogen aeration is completed, the culture solution from aerobic growth to the end of exponential growth is added to the hydrogen-producing medium at a 100% inoculum rate; xylose is added as a substrate in the hydrogen-producing medium, and the anaerobic growth period of 72 hours During the oxygen reaction (fermentation), samples were taken every 12 hours to collect the volume and content of hydrogen, and the anaerobic reaction (fermentation) temperature was 35°C.

The results of the total hydrogen production under the xylose concentration of 2~8g/L are shown in Figure 1. It can be seen that when the substrate xylose concentrations are 2, 4, 6, and 8g/L, the hydrogen production is respectively were 72.69mL, 93.73, 100.48, and 104.28mL, and the conversion rates of xylose were 93.45%, 63.45%, 58.3%, and 62.5%, respectively. Therefore, in the process of anaerobic fermentation, when the substrate concentration is increased, the hydrogen production will be increased accordingly, but the conversion rate of xylose is the largest at 2g/L.

Example 2

Under the condition of 1% inoculum rate, the method for preparing hydrogen from xylose comprises the following steps:

1) Take the Klebsiella oxytoca GS-4-08 strain (the strain disclosed in CN105524944A), activate it with the growth medium, and obtain the seed liquid; the formula of the growth medium is: yeast extract 5g/L, peptone 10g/L, chlorine Sodium chloride 10g/L.

2) Take the seed liquid and inoculate it in the sterilized growth medium. The bacterial activation temperature is 35°C, the rotation speed is 180r/min, and the aerobic growth is performed for 12 hours; The formula is: KH ₂ PO ₄ 0.5g/L, Na ₂ HPO ₄ ·12H ₂ O 1.57 g/L, MgSO ₄ ·7H ₂ O 0.1g/L.

3) After the nitrogen aeration is completed, the culture solution from aerobic growth to the end of exponential growth is added to the hydrogen-producing medium at an inoculation rate of 1%; xylose is added to the hydrogen-producing medium as a substrate, and the anaerobic growth period of 72 hours During the oxygen reaction (fermentation), samples were taken every 12 hours to collect the volume and content of hydrogen, and the anaerobic reaction (fermentation) temperature was 35°C.

The results of the total hydrogen production under the inoculation rate of 1% are shown in Figure 2. It can be seen that when the xylose concentration is 2g/L, the hydrogen production is 48.8mL, which is 100% of the inoculation rate under the same conditions. The hydrogen production of the hydrogen-producing medium was reduced by 13.8mL. Therefore, the inoculation rate is also one of the factors affecting the hydrogen production using xylose as a substrate, and a proper increase in the inoculation rate can increase the hydrogen production.

Claims (7)

1. one kind utilizes the method that hydrogen prepared by xylose, it is characterised in that comprise the following steps:

1) takeKlebsiella oxytocaGS-4-08 strain, cultivates and obtains seed liquor；

2) take in the bacterial growth media after seed liquor is inoculated in sterilizing, at 35 DEG C, then carry out aerobic growth；It is substantial amounts of that cultivation obtainsKlebsiella oxytocaGS-4-08 bacteria culture fluid；

3) carry out exposing nitrogen treatment to product hydrogen culture medium, after exposing nitrogen, be added to produce in hydrogen culture medium according to the rate of vaccination of 100% by bacteria culture fluid during aerobic growth to exponential growth latter stage；

4) anaerobic reaction, collects hydrogen.

The method utilizing xylose to prepare hydrogen the most according to claim 1, it is characterised in that in step 1), cultivates seed liquor with growth medium.

The method utilizing xylose to prepare hydrogen the most according to claim 1, it is characterised in that step 2) in, the formula producing hydrogen culture medium is: 0.5g/L KH₂PO₄、1.57g/L Na₂HPO₄·12H₂O、0.1g/L MgSO₄·7H₂O。

The method utilizing xylose to prepare hydrogen the most according to claim 1, it is characterised in that step 2) in, the pH value producing hydrogen culture medium is about 7.0.

The method utilizing xylose to prepare hydrogen the most according to claim 1, it is characterised in that step 2) in, at 35 DEG C, carry out aerobic growth 12h.

The method utilizing xylose to prepare hydrogen the most according to claim 1, it is characterised in that in step 3), xylose solution concentration is 2 ~ 8g/L.

The method utilizing xylose to prepare hydrogen the most according to claim 1, it is characterised in that in step 4), more than anaerobic reaction 48h.