阅读说明：本技术 一种利用白酒酿造副产物制备丁酸的方法 (Method for preparing butyric acid by utilizing white spirit brewing by-product ) 是由 何建英 李平 于 2021-09-17 设计创作，主要内容包括：本申请涉及白酒酿造副产物利用领域,具体公开了一种白酒酿造副产物制备丁酸的方法,包括以下步骤：将丢糟烘干后粉碎、过筛后,依次进行液化、糖化、水解、发酵和精馏；发酵步骤为：将水解所得物与黄水、底锅水混合,制得待发酵液,将丁酸梭菌接种到待发酵液中,用碳酸镁调节pH值至6-7,加入生物素,在35-40℃下厌氧发酵6-15天；精馏步骤为：将发酵所得物的pH值调节至3-4,离心,加入萃取液,混合均匀,然后在90-100℃、0.05-0.11MPa的条件下精馏。本申请的方法具有能对白酒酿造副产物进行资源化利用,生产出能调节白酒酸度的丁酸,工艺简单,产率高的优点。(The application relates to the field of utilization of white spirit brewing byproducts, and particularly discloses a method for preparing butyric acid from the white spirit brewing byproducts, which comprises the following steps: drying the waste lees, crushing, sieving, sequentially liquefying, saccharifying, hydrolyzing, fermenting and rectifying; the fermentation steps are as follows: mixing the hydrolyzed product with yellow water and water in a bottom boiler to obtain solution to be fermented, inoculating Clostridium butyricum into the solution to be fermented, adjusting pH to 6-7 with magnesium carbonate, adding biotin, and performing anaerobic fermentation at 35-40 deg.C for 6-15 days; the rectification steps are as follows: adjusting pH of the fermented product to 3-4, centrifuging, adding the extractive solution, mixing, and rectifying at 90-100 deg.C under 0.05-0.11 MPa. The method has the advantages of capability of performing resource utilization on the white spirit brewing by-products, capability of producing butyric acid capable of adjusting the acidity of the white spirit, simple process and high yield.)

1. A method for preparing butyric acid by utilizing a white spirit brewing byproduct is characterized by comprising the following steps: drying the waste lees, crushing, sieving, sequentially liquefying, saccharifying, hydrolyzing, fermenting and rectifying;

the fermentation steps are as follows: mixing the hydrolysate with yellow water and pot water according to the mass ratio of 1:0.5-1:1-1.5 to prepare a liquid to be fermented, inoculating clostridium butyricum into the liquid to be fermented, adjusting the pH value to 6-7 with magnesium carbonate, adding biotin, and carrying out anaerobic fermentation at 35-40 ℃ for 6-15 days, wherein the inoculation amount of clostridium butyricum is 5-10% wt of the liquid to be fermented, and the addition amount of biotin is 0.2-0.5 g/L;

the rectification steps are as follows: adjusting the pH value of the fermentation product to 3-4, centrifuging, adding an extraction liquid, mixing uniformly, and then rectifying at 90-100 ℃ under the pressure of 0.05-0.11MPa, wherein the mass ratio of the fermentation product to the extraction liquid is 1:3-3.5, and the extraction liquid is trialkylamine and n-octanol with the mass ratio of 1: 0.5-1.

2. The method for preparing butyric acid from a byproduct of liquor brewing according to claim 1, wherein the clostridium butyricum is cultured by the following culture method in the fermentation step: mixing the cellar sediment and distilled water according to the mass ratio of 1:3-5, heating in water bath at 80-85 deg.C for 10-15min, inoculating onto culture medium, wherein the inoculum size is 10-15% wt of the culture medium, and anaerobically activating at 35-37 deg.C and pH 6-6.5 for 10-20 h.

3. The method for preparing butyric acid by using a white spirit brewing byproduct according to claim 2, wherein the culture medium comprises the following components in percentage by weight: 2-4% of soluble starch, 1-2% of ammonium sulfate, 2-4% of yeast extract, 0.1-0.3% of sodium bicarbonate, 0.01-0.03% of manganese sulfate, 0.01-0.03% of magnesium sulfate, 0.001-0.002% of anhydrous calcium chloride and the balance of deionized water.

4. The method for preparing butyric acid by using a white spirit brewing byproduct according to claim 1, wherein the hydrolysis step specifically comprises: adding 10-12U/g cellulose complex enzyme into the saccharified product, adjusting pH to 4.5-5, and fermenting at 45-55 deg.C for 3-7 d.

5. The method for preparing butyric acid by using a white spirit brewing byproduct according to claim 4, wherein the compound cellulase is cellulase, cellobiase and xylanase in a mass ratio of 1:0.5-1: 0.2-0.5.

6. The method for preparing butyric acid by using a white spirit brewing byproduct according to claim 1, wherein: the drying temperature is 100-105 ℃, and the weight loss rate of the waste grains after drying is 40-50%.

7. The method for preparing butyric acid by using a white spirit brewing byproduct according to claim 1, wherein the liquefaction step specifically comprises: adding 70-100U/g alpha-amylase into the crushed waste lees, uniformly mixing, heating to 80-90 ℃, adjusting the pH value to 5.5-6.5, and fermenting for 3-5 d.

8. The method for preparing butyric acid by using a by-product from brewing white spirit according to claim 1, wherein the saccharification step specifically comprises: adding 60-80U/g saccharifying enzyme into the liquefied product, adjusting pH to 4.5-5, fermenting at 60-65 deg.C for 3-5d, and sterilizing.

9. The method of producing butyric acid using a byproduct of liquor brewing according to claim 1, wherein the trialkylamine is one selected from the group consisting of tripentylamine, trihexylamine, trioctylamine, and tridecylamine.

10. The method for preparing butyric acid from a white spirit brewing byproduct according to claim 1, wherein the spent grains are crushed and then hydrolyzed after being treated as follows: adding Aspergillus niger and Candida, fermenting at 33-37 deg.C and pH of 6.5-7 for 8-10 days, wherein the amount of Aspergillus niger is 0.03-0.05 wt% of distiller's grains, and the amount of Candida is 0.09-0.12 wt% of distiller's grains.

Technical Field

The application relates to the technical field of utilization of white spirit brewing byproducts, in particular to a method for preparing butyric acid by utilizing white spirit brewing byproducts.

Background

In recent years, besides partial treatment of the white wine fermentation byproducts by a small number of large-scale wine brewing enterprises, such as production of high-protein feed by using waste lees or preparation of yeast by using waste lees, but a large number of medium and small-scale enterprises directly discharge the white wine brewing byproducts without treatment basically, so that economic benefit is not provided, and environmental pollution is brought.

Butyric acid is an important raw material for synthesizing spices, is mainly used for synthesizing butyrate and cellulose butyrate, butyrate has different fruit flavors and is widely applied to the fields of essence, food additives, medicine and the like, cellulose butyrate has excellent heat resistance, light resistance and moisture resistance and simultaneously has good forming and stability, the butyrate is used for manufacturing thermoforming signboards, glasses, automobile steering wheels and the like, varnish and molding powder can be widely manufactured, n-butyric acid is used as an organic acid and is an important component for forming the taste of white spirit when being blended into the white spirit, the taste and the taste of the white spirit can be adjusted by adjusting the acid, the bitterness, the foreign flavor and the dry and spicy feeling are eliminated, and the aftertaste is increased.

In view of the above-mentioned related technologies, the inventors consider that how to effectively utilize the by-products generated during brewing of white spirit, and the production of butyric acid for adjusting the acidity of white spirit is an urgent problem to be solved.

Disclosure of Invention

In order to utilize white spirit to brew the by-product and produce butyric acid, reduce the pollution of the direct emission of by-product to the environment, this application provides a method for preparing butyric acid by utilizing white spirit to brew the by-product.

In a first aspect, the application provides a method for preparing butyric acid by utilizing a white spirit brewing byproduct, which adopts the following technical scheme:

a method for preparing butyric acid by utilizing a white spirit brewing byproduct comprises the following steps: drying the waste lees, crushing, sieving, sequentially liquefying, saccharifying, hydrolyzing, fermenting and rectifying;

the fermentation steps are as follows: mixing the hydrolysate with yellow water and pot water according to the mass ratio of 1:0.5-1:1-1.5 to prepare a liquid to be fermented, inoculating clostridium butyricum into the liquid to be fermented, adjusting the pH value to 6-7 with magnesium carbonate, adding biotin, and carrying out anaerobic fermentation at 35-40 ℃ for 6-15 days, wherein the inoculation amount of clostridium butyricum is 5-10% wt of the liquid to be fermented, and the addition amount of biotin is 0.2-0.5 g/L;

the rectification steps are as follows: adjusting the pH value of the fermentation product to 3-4, centrifuging, adding an extraction liquid, mixing uniformly, and then rectifying at 90-100 ℃ under the pressure of 0.05-0.11MPa, wherein the mass ratio of the fermentation product to the extraction liquid is 1:3-3.5, and the extraction liquid is trialkylamine and n-octanol with the mass ratio of 1: 0.5-1.

By adopting the technical scheme, the spent grains are dried and crushed and then are liquefied, saccharified, hydrolyzed, fermented and rectified, because the spent grains contain certain moisture, the spent grains have certain acidity, but the moisture content in the spent grains is higher, the acidity of the spent grains is overhigh, and then the growth and the reproduction of microorganisms are influenced, and rice hulls contained in the spent grains are a lignocellulose raw material and consist of cellulose, hemicellulose, lignin and silicon dioxide, wherein the cellulose and the hemicellulose can be hydrolyzed, but the lignin can not be hydrolyzed, and the hydrolysis of the cellulose and the hemicellulose can be hindered, so the bonding layer of the lignin and the hemicellulose is weakened, the crystallinity is reduced, the lignin is easy to be decomposed, the spent grains are dried to remove a part of moisture first, the acidity is reduced, and the spent grains are suitable for the growth and the reproduction of the microorganisms, then crushing, stirring to reduce the crystallinity of lignin and hemicellulose inside the rice husk, so that the rice husk in the waste lees is easy to decompose.

And then clostridium butyricum is inoculated into the waste lees, the yellow water and the bottom boiler water, the waste lees, the yellow water and the bottom boiler water contain glucose, residual starch and other substances which are not utilized in the wine brewing process, microbial flora can be generated after fermentation, the relationship of mutual growth, symbiosis and antagonism among microorganisms is effectively utilized, the acid production effect is excellent, and the pH value is adjusted by magnesium carbonate to provide carbon dioxide for the microorganisms. Then the extract liquor is used for extracting and separating the fermentation liquor, trialkylamine and n-octanol are used as the extract liquor, the two phases are balanced quickly, the interface is clear, the butyric acid is extracted in the form of trialkylammonium butyrate, and then the solution is rectified at 90-100 ℃ to decompose the trialkylammonium butyrate into butyric acid and trialkylamine, so that the product is obtained, the preparation method is simple, and the yield is high.

Preferably, in the fermentation step, the clostridium butyricum is prepared by culturing according to the following culture method: mixing the cellar sediment and distilled water according to the mass ratio of 1:3-5, heating in water bath at 80-85 deg.C for 10-15min, inoculating onto culture medium, wherein the inoculum size is 10-15% wt of the culture medium, and anaerobically activating at 35-37 deg.C and pH 6-6.5 for 10-20 h.

By adopting the technical scheme, a large amount of anaerobic bacillus, methane bacteria, clostridium butyricum and lactic acid bacteria are enriched in the cellar bottom mud, the cellar bottom mud is mixed with distilled water, the mixture is heated in a water bath to kill non-spore bacteria, then the non-spore bacteria are inoculated and cultured, and the strains can rapidly grow and reproduce under the proper temperature and acid-base environment.

Preferably, the culture medium comprises the following components in percentage by weight: 2-4% of soluble starch, 1-2% of ammonium sulfate, 2-4% of yeast extract, 0.1-0.3% of sodium bicarbonate, 0.01-0.03% of manganese sulfate, 0.01-0.03% of magnesium sulfate, 0.001-0.002% of anhydrous calcium chloride and the balance of deionized water.

By adopting the technical scheme, the yeast extract contains V necessary for growth of clostridium butyricum_B12Growth factors such as the yeast extract and the ammonium sulfate can promote the growth and metabolism of thalli, the yeast extract is used as an organic nitrogen source, the ammonium sulfate is used as an inorganic nitrogen source, and the yeast extract and the ammonium sulfate are matched to greatly contribute to the fermentation effect; the effect of magnesium ions on the enzymatic activity of clostridium butyricum is good, soluble starch and sodium bicarbonate are used as carbon sources, manganese sulfate can promote the generation of spores, and the growth of clostridium butyricum is promoted by a culture medium prepared by optimizing various components.

Preferably, the hydrolysis step is specifically: adding 10-12U/g cellulose complex enzyme into the saccharified product, adjusting pH to 4.5-5, and fermenting at 45-55 deg.C for 3-7 d.

By adopting the technical scheme, because the waste lees contain the rice hulls which are composed of cellulose, hemicellulose, lignin and the like, the liquefied and saccharified waste lees are hydrolyzed by using a cellulose complex enzyme, so that the cellulose is decomposed to form reducing sugar.

Preferably, the compound cellulase is cellulase, cellobiase and xylanase in a mass ratio of 1:0.5-1: 0.2-0.5.

By adopting the technical scheme, the cellulase can convert cellulose into monosaccharide or disaccharide, the cellobiase can continuously convert disaccharide into monosaccharide, and the xylanase can hydrolyze hemicellulose into pentose, so that cellulose and the like in waste lees are converted into reducing sugar.

Preferably, the drying temperature is 100-105 ℃, and the weight loss rate of the waste lees after drying is 40-50%.

By adopting the technical scheme, after the spent grains are dried at high temperature, the crystallinity of cellulose and hemicellulose can be reduced, part of water in the spent grains is removed, and the acidity is reduced, so that the spent grains are suitable for the growth and reproduction of microorganisms; in addition, the starch in the waste lees can be pasted, so that the enzyme can quickly find out the enzyme cutting sites during liquefaction and saccharification.

Preferably, the liquefaction step is specifically: adding 70-100U/g alpha-amylase into the crushed waste lees, uniformly mixing, heating to 80-90 ℃, adjusting the pH value to 5.5-6.5, and fermenting for 3-5 d.

By adopting the technical scheme, the spent grains are liquefied by using alpha-amylase, and the alpha-amylase can act on alpha-1, 4-glycosidic bond or alpha-1, 6-glycosidic bond of starch to randomly hydrolyze the starch from the inside and hydrolyze the starch into dextrin and a small amount of maltose.

Preferably, the saccharification step specifically comprises: adding 60-80U/g saccharifying enzyme into the liquefied product, adjusting pH to 4.5-5, fermenting at 60-65 deg.C for 3-5d, and sterilizing.

By adopting the technical scheme, the saccharifying enzyme can decompose the liquefied starch in the waste lees into single glucose molecules, so that the subsequent clostridium butyricum fermentation can be conveniently utilized.

Preferably, the trialkylamine is selected from one of tripentylamine, trihexylamine, trioctylamine and tridecylamine.

By adopting the technical scheme, tripentylamine, trihexylamine, trioctylamine and tridecylamine can react with butyric acid to generate trialkylamine butyrate, and the trialkylamine butyrate can be decomposed during rectification, so that the butyric acid can be conveniently collected.

Preferably, the waste lees is crushed and then hydrolyzed after being treated as follows: adding Aspergillus niger and Candida, fermenting at 33-37 deg.C and pH of 6.5-7 for 8-10 days, wherein the amount of Aspergillus niger is 0.03-0.05 wt% of distiller's grains, and the amount of Candida is 0.09-0.12 wt% of distiller's grains.

By adopting the technical scheme, the spent grains are mixed with aspergillus niger and candida before being liquefied, so that the content of reducing sugar in the spent grains can be further improved, and the yield of butyric acid is improved.

In summary, the present application has the following beneficial effects:

1. the preparation method comprises the steps of preparing butyric acid by using a white spirit brewing by-product, recovering spent grains, yellow water and pot bottom water, recycling fermentation by-products, avoiding causing fragile environmental pollution, reducing the crystallinity of cellulose in the spent grains by drying and crushing, enabling the cellulose to be easy to decompose, then liquefying, saccharifying, hydrolyzing, fermenting and rectifying, adjusting the pH value by using magnesium carbonate after clostridium butyricum is inoculated during fermentation, adding biotin to enable the pH value of fermentation liquor to be suitable for growth and reproduction of clostridium butyricum, accelerating the glucose oxidation capacity, improving the glycolysis speed, then adopting trialkylamine and n-octanol as extracting agents to enable the butyric acid to react with the trialkylamine to grow trialkylamine butyrate, and then dispersing the butyric acid during rectification to generate butyric acid, thereby completing the preparation of the butyric acid.

2. In the application, yeast extract is preferably used as an organic nitrogen source, ammonium sulfate is used as an inorganic nitrogen source, the yeast extract and the ammonium sulfate are mutually matched to be used as the nitrogen source, water-soluble starch is used as a carbon source, and the catalytic activity of magnesium ions and manganese ions is utilized to improve the culture amount of clostridium butyricum on a culture medium and improve the growth activity of clostridium butyricum.

3. In this application will lose in a wretched state stoving and smash the back, use aspergillus niger and candida to ferment, then carry out steps such as liquefaction, saccharification again, aspergillus niger and candida can further improve and lose in a wretched state reducing sugar and obtain content when losing in a wretched state in the fermentation to improve the productivity of butyric acid. .

Detailed Description

Preparation example of culture Medium

Preparation example 1: 20g of soluble starch, 10g of ammonium sulfate, 20g of yeast extract, 1g of sodium bicarbonate, 0.1g of manganese sulfate, 0.1g of magnesium sulfate, 0.01g of anhydrous calcium chloride and 948.79g of deionized water are mixed.

Preparation example 2: 40g of soluble starch, 20g of ammonium sulfate, 40g of yeast extract, 3g of sodium bicarbonate, 0.3g of manganese sulfate, 0.3g of magnesium sulfate, 0.02g of anhydrous calcium chloride and 896.38g of deionized water are mixed.

Preparation example 3: the difference from preparation example 1 is that an equal amount of glucose was used instead of soluble starch.

Preparation example 4: the difference from preparation example 1 is that an equal amount of peptone was used instead of yeast extract.

Preparation example 5: the difference from preparation example 1 is that peptone was used in place of yeast extract in an equal amount and ammonia was used in place of ammonium sulfate in an equal amount.

Preparation example 6: the difference from preparation example 1 is that equal amounts of urea were used instead of yeast extract.

Examples

In the embodiment, the waste lees, the yellow water and the bottom pot water are selected from Luzhou Laojiao Co., Ltd, the content of the waste lees is shown in Table 1, the component analysis of the yellow water is shown in Table 2, the component analysis of the bottom pot water is shown in Table 3, the pit bottom mud is selected from Luzhou Laojiao Co., Ltd, the pit age is 40 years, the sampling depth is 40cm away from the pit bottom, the component analysis is shown in Table 4, the Aspergillus niger is selected from Yiyuan Kangyuan Biotech Co., Ltd, and the product number is 005; the Candida is selected from Wenzhou Cheng chemical technology Co., Ltd, and has model number of SC 01; the cellulase is selected from 10000U/g from the biological engineering Limited company of Jinan Baismi, and the cellobiase is selected from 1000U/g from the biotechnology development Limited company of Xiasan (Beijing) and has the model of FFY-3401; the xylanase is selected from 200000U/g of Jinan Baismi bioengineering limited company; the alpha-amylase is selected from Shandong Jideno biological enzyme company Limited, 20000U/mL; the saccharifying enzyme is selected from Shandong Longong bioengineering Co., Ltd, 100000U/mL; the biotin is selected from Jiangsu Bairong Biotech limited, having a product number of 0642.

TABLE 1 composition analysis of spent grains

TABLE 2 analysis of the composition of yellow water

TABLE 3 composition analysis of bottom boiler water

TABLE 4 compositional analysis of pit mud

Example 1: a method for preparing butyric acid by utilizing a white spirit brewing byproduct comprises the following steps:

s1, drying: drying 2kg of waste lees at 105 ℃ until the weight loss rate is 50%, crushing, and sieving by a 40-mesh sieve;

s2, liquefaction: adding 90U/g alpha-amylase into 1kg of crushed waste lees, uniformly mixing, heating to 90 ℃, adjusting the pH value to 6, and fermenting for 3 d;

s3, saccharification: adding 70U/g saccharifying enzyme into 1kg of liquefied product, adjusting pH to 4.5, fermenting at 60 deg.C for 3d, and sterilizing at 120 deg.C for 20 min;

s4, hydrolysis: adding 12U/g cellulose complex enzyme into 1kg of saccharification resultant, adjusting pH to 4.8, and fermenting at 50 ℃ for 7d, wherein the cellulose complex enzyme is cellulase, cellobiase and xylanase in a mass ratio of 1:0.5: 0.2;

s5, fermentation: mixing 1kg of hydrolysate with yellow water and bottom boiler water according to the mass ratio of 1:1:1 to prepare a liquid to be fermented, inoculating clostridium butyricum into the liquid to be fermented, adjusting the pH value to 6.5 by using magnesium carbonate, adding biotin, performing anaerobic fermentation for 15 days at 37 ℃, wherein the inoculation amount of clostridium butyricum is 15% wt of the liquid to be fermented, the addition amount of the biotin is 0.2g/L, and the clostridium butyricum is prepared by the following method: mixing the cellar sediment and distilled water according to the mass ratio of 1:5, heating in water bath for 10min at 80 ℃, inoculating the mixture onto a culture medium, wherein the inoculation amount is 10% wt of the culture medium, and performing anaerobic activation for 20h under the environment that the temperature is 35 ℃ and the pH value is 6.5, wherein the culture medium is prepared by the preparation example 1;

s6, rectification: adjusting the pH value of 1kg of fermentation product to 3.5, centrifuging, adding an extraction liquid, mixing uniformly, and then rectifying for 80min at 90 ℃ and 0.05MPa, wherein the mass ratio of the fermentation product to the extraction liquid is 1:3.5, the extraction liquid is trialkylamine and n-octanol, and the trialkylamine is tripentylamine.

Example 2: a method for producing butyric acid from a byproduct of brewing white spirit, which is different from example 1 in that the medium of step S5 is prepared according to preparation example 2.

Preparation example 3: a method for producing butyric acid from a byproduct of brewing white spirit, which is different from example 1 in that the medium of step S5 is prepared according to preparation example 3.

Example 4: a method for producing butyric acid from a byproduct of brewing white spirit, which is different from example 1 in that the medium of step S5 is prepared according to preparation example 4.

Example 5: a method for producing butyric acid from a byproduct of brewing white spirit, which is different from example 1 in that the medium of step S5 is prepared according to preparation example 5.

Example 6: a method for producing butyric acid from a byproduct of brewing white spirit, which is different from example 1 in that the medium of step S5 is prepared according to preparation example 6.

Example 7: a method for preparing butyric acid from a by-product of liquor brewing, which is different from example 1 in that the mixture of cellar mud and distilled water is inoculated on the medium in an amount of 10% by weight of the medium in step S5.

Example 8: a method for preparing butyric acid from a byproduct of liquor brewing is different from example 1 in that biotin is added in an amount of 0.5g/L in step S5.

Example 9: the method for preparing butyric acid from the by-product of liquor brewing is different from the method in example 1 in that the cellulose complex enzyme in the step S4 is cellulase and xylanase in the mass ratio of 1: 0.2.

Example 10: a method for preparing butyric acid from a byproduct of liquor brewing, which is different from example 1 in that in step S1, the sieved spent grains are hydrolyzed by the following steps: adding Aspergillus niger and Candida in 1kg of crushed distiller's grains, and fermenting at 35 deg.C and pH 6.5 for 10 days, wherein the addition amount of Aspergillus niger is 0.03 wt% of the distiller's grains, and the addition amount of Candida is 0.09 wt% of the distiller's grains.

Example 11: a method for preparing butyric acid from a byproduct of liquor brewing is different from example 10 in that Candida spp is added in an amount of 0.03 wt% of spent grains.

Example 12: a method for preparing butyric acid from a byproduct of liquor brewing is different from example 10 in that Candida spp is added in an amount of 0.21% by weight of spent grains.

Comparative example

Comparative example 1: a method for preparing butyric acid from a byproduct of liquor brewing, which is different from example 1 in that step S4 is performed, and then step S2 and step S3 are performed.

Comparative example 2: a method for preparing butyric acid from a byproduct of liquor brewing is different from example 1 in that hydrolysis and saccharification are carried out simultaneously, and the specific method is as follows: adding compound enzyme of saccharifying enzyme and cellulose into the liquefied product, controlling temperature at 50 deg.C, adjusting pH to 4.8, and fermenting for 5 d.

Comparative example 3: a method for preparing butyric acid from a byproduct of liquor brewing is different from example 1 in that hydrolysis and saccharification are carried out simultaneously, and the specific method is as follows: adding compound enzyme of saccharifying enzyme and cellulose into the liquefied product, controlling temperature at 60 deg.C, adjusting pH to 4.5, and fermenting for 5 d.

Comparative example 4: a method for preparing butyric acid by utilizing a white spirit brewing byproduct is different from the embodiment 1 in that the waste lees is soaked in a sodium hydroxide solution with the weight percentage concentration of 1% before being dried, the temperature is 120 ℃, and the time is 2 hours.

Comparative example 5: a method for preparing butyric acid from a byproduct of liquor brewing, which is different from example 1 in that step S2 is not performed.

Comparative example 6: a method for preparing butyric acid from a byproduct of liquor brewing, which is different from example 1 in that step S3 is not performed.

Comparative example 7: a method for preparing butyric acid from a byproduct of liquor brewing, which is different from example 1 in that step S6 is not performed.

Comparative example 8: a method for preparing butyric acid from a byproduct of liquor brewing, which is different from example 1 in that tributyl phosphate is used in place of tripentylamine in step S6 in an equal amount.

Comparative example 9: a method for producing butyric acid from a byproduct of liquor brewing, which is different from example 1 in that biotin is not added in step S5.

Performance test

Firstly, mixing the cellar sediment and distilled water according to the mass ratio of 1:5, heating the mixture in a water bath at 80 ℃ for 10min, inoculating the mixture on the culture medium prepared in the preparation example 1, wherein the inoculation amount is 10% wt of the culture medium, carrying out anaerobic activation for 20h in the environment with the temperature of 35 ℃ and the pH value of 6.5, inoculating the mixture of the cellar sediment and the distilled water on the culture medium prepared in the preparation examples 2-6 according to the same method, recording the concentration of clostridium butyricum by adopting a blood counting plate method, and recording the detection result in a table 4.

TABLE 4 Effect of different media on the concentration of butyric acid Carboxylic groups

Preparation example	Clostridium butyricum concentration (10)8/mL）
		Preparation example 1	2.172
Preparation example 2	2.541
		Preparation example 3	2.021
Preparation example 4	1.943
		Preparation example 5	1.975
Preparation example 6	1.965

As can be seen from the data in Table 4, the culture medium prepared in preparation examples 1-2 is used for culturing Clostridium butyricum carried in pit mud, the culture medium can use soluble starch as a carbon source of Clostridium butyricum, and yeast extract and ammonium sulfate as a nitrogen source combined and matched by organic nitrogen and inorganic nitrogen, so that the cost of the culture medium can be reduced, and the culture quantity of Clostridium butyricum can be increased.

In preparation example 3, glucose was used as a carbon source, the concentration of clostridium butyricum was reduced compared with that in preparation example 1, peptone was used instead of yeast extract and was used in combination with ammonium sulfate as a nitrogen source in preparation example 4, peptone was used instead of yeast extract as an organic nitrogen source and ammonia was used instead of ammonium sulfate as an inorganic nitrogen source in preparation example 5, and the concentration of clostridium butyricum prepared was inferior to that in preparation example 1; in comparative example 6, the concentration of clostridium butyricum cultured in the culture medium prepared by using urea instead of yeast extract as an inorganic nitrogen source is lower than that of the clostridium butyricum cultured in preparation example 1.

Next, after the pulverization, liquefaction and saccharification in accordance with the methods of examples 1 and 10 to 12 and comparative examples 1 to 4, the content of reducing sugars in the saccharified product was measured in accordance with the DNS (3, 5-dinitrosalicylic acid) method, and the results of the measurements are shown in Table 4.

TABLE 4 Effect of liquefaction and saccharification on reducing sugar concentration

Item	Reducing sugar concentration (g/L)
		Example 1	62.8
Example 10	65.5
		Example 11	63.4
Example 12	64.1
		Comparative example 1	58.2
Comparative example 2	60.2
		Comparative example 3	61.5
Comparative example 4	60.3
		Comparative example 5	50.3
Comparative example 6	49.7

As can be seen from the data in Table 4, the content of reducing sugar in the saccharified product was determined by drying, liquefying and saccharifying the spent grain, and in example 1, the content of reducing sugar in the residual starch in the spent grain was high after the treatment with alpha-amylase and saccharifying enzyme.

In examples 10 to 12, before liquefying spent grains, Aspergillus niger and Candida were fermented at a ratio of 1:3, and the content of reducing sugar in the saccharified product was further increased, while the content of Candida was decreased or increased, but the content of reducing sugar was decreased.

Comparative example 1 compared to example 1, hydrolysis followed by liquefaction and saccharification, cellulose followed by hydrolysis followed by reduction of starch, resulted in a reduction of the reducing sugar content.

Comparative example 2 and comparative example 3 compared with example 1, hydrolysis and saccharification were carried out simultaneously, and the fermentation temperature in comparative example 2 was 50 ℃ and the pH was 4.8, at which the temperature and pH were not suitable for saccharification by the saccharifying enzyme, the fermentation temperature in comparative example 3 was 60 ℃ and the pH was 4.5, the temperature and pH in comparative example 2 were not suitable for saccharification, and the temperature and pH in comparative example 3 were not suitable for hydrolysis, resulting in a decrease in the content of reducing sugars in the saccharified product.

In the comparative example 4, the waste distiller's grains are subjected to alkali treatment by using sodium hydroxide, the rice hulls contain rice hulls, the rice hulls contain lignin, hydrolysis is affected, and cellulose loss is caused by using alkali liquor treatment, so that the content of reducing sugar is reduced.

In comparative example 5 where no liquefaction of S2 was performed and in comparative example 6 where no saccharification of S3 was performed, the reducing sugar concentrations of comparative example 5 and comparative example 6 were significantly reduced compared to example 1.

And thirdly, preparing butyric acid according to the methods in the examples and the comparative examples, detecting the concentration of the butyric acid in the rectified product, and calculating the yield of the butyric acid. Determining butyric acid yield by gas chromatography with HP-INNOWAX capillary column (30 m × 0.323mm × 0.50 μm); carrier gas: high purity nitrogen; sample inlet temperature: 250 ℃; FID detector temperature: 250 ℃; internal standard: propionic acid; sample introduction amount: 0.4 mu L; the peak time of butyric acid is 9.9min, the content of butyric acid is calculated by peak area and standard curve, the purity of butyric acid in the rectification liquid is detected by high performance liquid chromatography, and the detection result is recorded in table 5.

TABLE 5 yield of butyric acid

Item	Butyric acid concentration (g/L)	Butyric acid yield (%)	Item	Butyric acid concentration (g/L)	Butyric acid yield (%)
						Example 1	45.4	85.4	Example 12	46.8	81.5
Example 2	44.9	85.1	Comparative example 1	28.4	68.5
						Example 3	39.2	75.2	Comparative example 2	29.4	69.4
Example 4	38.8	72.4	Comparative example 3	28.8	67.8
						Example 5	39.1	74.8	Comparative example 4	29.1	69.7
Example 6	39.9	78.1	Comparative example 5	27.5	67.9
						Example 7	45.1	80.4	Comparative example 6	28.1	68.4
Example 8	45.2	85.2	Comparative example 7	28.7	68.5
						Example 9	30.1	72.5	Comparative example 8	29.4	69.4
Example 10	48.6	83.5	Comparative example 9	33.7	71.4
						Example 11	47.2	82.7	/	/	/

As can be seen from the data in Table 5, the butyric acid prepared in example 1 and example 2 has high concentration and high yield, and has high utilization rate for spent grains, yellow water and pot water.

In examples 3 to 6, the media prepared in preparation examples 3 to 6 were used, respectively, and the concentration of butyric acid prepared in examples 3 to 6 was inferior to that of examples 1 and 2 because the media cultured Clostridium butyricum of preparation examples 1 to 2 had insufficient activity.

In example 7, the mixture of the pit mud and the distilled water was inoculated in an amount of 10% by weight on the medium, and the butyric acid produced by liquefaction, saccharification, hydrolysis, fermentation, etc. had a high concentration and a high yield.

The addition amount of biotin in example 8 was 0.8g/L, and the change in the content of butyric acid was small and the change in the yield was insignificant in example 8 compared with the concentration and yield of butyric acid in example 1.

In example 10, before the spent grains were liquefied, the concentration of butyric acid produced was increased by fermentation using Aspergillus niger and Candida, and the yield was further improved.

In examples 11 and 12, the concentration and yield of butyric acid were reduced compared to example 10 by changing the ratio of the amounts of aspergillus niger and candida, indicating that the yield of butyric acid was significantly increased when the amounts of aspergillus niger and candida were 1:3.

Comparative example 1 compared to example 1, hydrolysis followed by liquefaction and saccharification, cellulose hydrolysis followed by starch reduction, reduced reducing sugar content and reduced butyric acid content were achieved.

Comparative example 2 and comparative example 3 compared with example 1, hydrolysis and saccharification were carried out simultaneously, and the yield of butyric acid produced was decreased when the fermentation temperature was 50 ℃ and the pH was 4.8 in comparative example 2, at which the temperature and pH were not suitable for saccharification by the saccharifying enzyme, when the fermentation temperature was 60 ℃ and the pH was 4.5 in comparative example 3, when the temperature and pH were not suitable for saccharification in comparative example 2 and when the temperature and pH were not suitable for hydrolysis in comparative example 3.

In the comparative example 4, the waste distiller's grains are subjected to alkali treatment by using sodium hydroxide, the rice hulls contain rice hulls, the rice hulls contain lignin, hydrolysis is affected, and cellulose loss is caused by using alkali liquor treatment, so that the content of reducing sugar is reduced, and the yield of butyric acid is increased.

Comparative example 5, in which no liquefaction of S2 was performed, and comparative example 6, in which no saccharification of S3 was performed, significantly decreased the reducing sugar concentration and yield of butyric acid in comparative example 5 and comparative example 6, as compared to example 1.

In comparative example 7, compared with example 1, the concentration of butyric acid in the fermentation broth obtained after fermentation was reduced and the yield was reduced compared with example 1 without rectification.

In the comparative example 8, tributyl phosphate is used to replace tripentylamine as an extracting agent, and after extraction and rectification, the concentration of butyric acid in the product is low and the yield is reduced.

In comparative example 9, biotin was not added, and the concentration of butyric acid after rectification was decreased and the yield was decreased as compared with example 1.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.