Method for producing ethanol through propagation fermentation of co-fermentation saccharomycetes

Abstract

The invention relates to the field of ethanol production, in particular to a method for producing ethanol through propagation fermentation of co-fermentation saccharomycetes. The method comprises the following steps: performing propagation on activated saccharomycetes to obtain a seed solution, and then inoculating the seed solution into a fermentation culture medium for fermentation to obtain ethanol, wherein in the propagation process, the stirring rotating speed is controlled to be 40-100 rpm, the ventilation ratio is 0-0.4 vvm, and the liquid loading amount is 60-70% by volume; and the saccharomycetes is saccharomyces cerevisiae, and the preservation number is CGMCC No.16830. Compared with a traditional saccharomycetes propagation method, micro-anaerobic propagation is adopted in the propagation process, the process energy consumption can be reduced, the equipment utilization rate can be increased, and the strain fermentation performance can be improved; and then, the seed solution is fermented, so that the metabolism efficiency of the strain on arabinose and xylose can be remarkably improved, and the ethanol yield is improved.

Description

technical field

[0001] The invention relates to the field of ethanol production, in particular to a method for producing ethanol by co-fermenting yeast expansion and fermentation. Background technique

[0002] Cellulosic raw materials are the most abundant renewable resources in nature. my country has an annual output of 600-700 million tons of straw alone. If 100 million tons of ethanol can be used to produce ethanol, the output can reach 20 million tons, which can alleviate the problem of tight oil supply and Food shortage problem. However, the use of biotechnology to transform fiber resources faces certain difficulties. Cellulosic raw materials are pretreated to produce hemifibers that are easily hydrolyzed, but the products of hemicellulose hydrolysis (xylose, arabinose) cannot be hydrolyzed by the usual Saccharomyces cerevisiae. Efficient utilization, so the efficiency of ethanol production by fermentation is limited to a certain extent. Therefore, improving the utiliza...

Examples

preparation example 1

[0050] This preparation example is used to illustrate the preparation method of cellulose raw material enzymatic hydrolysis product

[0051] (1) Pretreatment of cellulose raw materials

[0052] Cut 1000 grams of impurity-free corn stalks (water content 10%) into small pieces not exceeding 1.2 cm x 0.5 cm x 1.0 cm, maintain a pressure of 1.70 MPa at 195 ° C for 5 minutes, and then release the pressure to complete steam explosion. Stir and mix the obtained steam explosion product with 70°C water at a mass ratio of 1:3 for 30 minutes, and then use a LW400 decanter centrifuge (Zhangjiagang Huada Centrifuge Manufacturing Co., Ltd.) to perform solid-liquid separation at a speed of 900 rpm , Obtain 3000 grams of water-washed steam explosion product (moisture content is 70% by weight) altogether.

[0053] (2) Enzymolysis

[0054] Add water in the enzymolysis tank, and under agitation, add the first batch of step (1) washed steam explosion product, the amount of the first batch of ad...

Embodiment 1

[0057] This embodiment is used to illustrate the method for ethanol production by yeast fermentation of the present invention

[0058] (1) activation

[0059] Yeast strain (S.C araABD) was activated with YEPX medium, and the activation conditions included: rotating speed 200 rpm, constant temperature shaker at 30°C, activation for 20 hours, to obtain an activation solution.

[0060] (2) Expansion training

[0061] The activation solution is inserted into the expansion tank equipped with primary expansion culture medium (yeast extract 10g / L, peptone 20g / L, glucose 20g / L) by 1.0% (V / V) and carries out expansion cultivation. 60% by volume, expansion conditions 30±1°C, pH 5.0±0.1 (adjusted by ammonia water), stirring speed 80-100rpm, no ventilation during the expansion process, expansion 12h, to obtain the primary expansion seed liquid.

[0062] The technical conditions and culture medium of the secondary expansion are the same as those of the primary, and the inoculum size is 2...

Embodiment 2

[0067] This embodiment is used to illustrate the method for ethanol production by yeast fermentation of the present invention

[0068] Carry out fermentation to produce ethanol according to the method described in Example 1, the difference is that sterile air is passed through during the primary expansion and secondary expansion, the ventilation rate is 0.05vvm, and the liquid filling volume is 65% by volume. The stirring speed is 60-80rpm.

[0069] After the secondary expansion, use an optical microscope to detect the number of yeast: 184 million / ml, budding rate: 18.3%, and mortality: 0.5%.

[0070] After the fermentation, the contents of ethanol, glucose, xylose and arabinose in the fermentation products were measured, and the ethanol yield, xylose consumption rate and arabinose consumption rate were calculated. The specific results are shown in Table 1.

technical field

[0001] The invention relates to the field of ethanol production, in particular to a method for producing ethanol by co-fermenting yeast expansion and fermentation. Background technique

[0002] Cellulosic raw materials are the most abundant renewable resources in nature. my country has an annual output of 600-700 million tons of straw alone. If 100 million tons of ethanol can be used to produce ethanol, the output can reach 20 million tons, which can alleviate the problem of tight oil supply and Food shortage problem. However, the use of biotechnology to transform fiber resources faces certain difficulties. Cellulosic raw materials are pretreated to produce hemifibers that are easily hydrolyzed, but the products of hemicellulose hydrolysis (xylose, arabinose) cannot be hydrolyzed by the usual Saccharomyces cerevisiae. Efficient utilization, so the efficiency of ethanol production by fermentation is limited to a certain extent. Therefore, improving the utiliza...

Examples

preparation example 1

[0050] This preparation example is used to illustrate the preparation method of cellulose raw material enzymatic hydrolysis product

[0051] (1) Pretreatment of cellulose raw materials

[0052] Cut 1000 grams of impurity-free corn stalks (water content 10%) into small pieces not exceeding 1.2 cm x 0.5 cm x 1.0 cm, maintain a pressure of 1.70 MPa at 195 ° C for 5 minutes, and then release the pressure to complete steam explosion. Stir and mix the obtained steam explosion product with 70°C water at a mass ratio of 1:3 for 30 minutes, and then use a LW400 decanter centrifuge (Zhangjiagang Huada Centrifuge Manufacturing Co., Ltd.) to perform solid-liquid separation at a speed of 900 rpm , Obtain 3000 grams of water-washed steam explosion product (moisture content is 70% by weight) altogether.

[0053] (2) Enzymolysis

[0054] Add water in the enzymolysis tank, and under agitation, add the first batch of step (1) washed steam explosion product, the amount of the first batch of ad...

Embodiment 1

[0057] This embodiment is used to illustrate the method for ethanol production by yeast fermentation of the present invention

[0058] (1) activation

[0059] Yeast strain (S.C araABD) was activated with YEPX medium, and the activation conditions included: rotating speed 200 rpm, constant temperature shaker at 30°C, activation for 20 hours, to obtain an activation solution.

[0060] (2) Expansion training

[0061] The activation solution is inserted into the expansion tank equipped with primary expansion culture medium (yeast extract 10g / L, peptone 20g / L, glucose 20g / L) by 1.0% (V / V) and carries out expansion cultivation. 60% by volume, expansion conditions 30±1°C, pH 5.0±0.1 (adjusted by ammonia water), stirring speed 80-100rpm, no ventilation during the expansion process, expansion 12h, to obtain the primary expansion seed liquid.

[0062] The technical conditions and culture medium of the secondary expansion are the same as those of the primary, and the inoculum size is 2...

Embodiment 2

[0067] This embodiment is used to illustrate the method for ethanol production by yeast fermentation of the present invention

[0068] Carry out fermentation to produce ethanol according to the method described in Example 1, the difference is that sterile air is passed through during the primary expansion and secondary expansion, the ventilation rate is 0.05vvm, and the liquid filling volume is 65% by volume. The stirring speed is 60-80rpm.

[0069] After the secondary expansion, use an optical microscope to detect the number of yeast: 184 million / ml, budding rate: 18.3%, and mortality: 0.5%.

[0070] After the fermentation, the contents of ethanol, glucose, xylose and arabinose in the fermentation products were measured, and the ethanol yield, xylose consumption rate and arabinose consumption rate were calculated. The specific results are shown in Table 1.

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