Method for increasing yield of ethanol prepared from distilled spirit distiller grains
阅读说明：本技术 提升白酒丟糟制备乙醇产率的方法 (Method for increasing yield of ethanol prepared from distilled spirit distiller grains ) 是由 雷翔云 熊燕飞 邓波 敖灵 李勇 李嘉 俞佳 刘颖捷 曾珊 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种提升白酒丟糟制备乙醇产率的方法,属于农副产品再利用领域。本发明为提高白酒丟糟利用率,并提升乙醇发酵的产率,提供了一种提升白酒丟糟制备乙醇产率的方法,该方法先对白酒丢糟湿度进行调整,然后采用稀酸温和水解,保障较高还原糖得率,并降低发酵抑制物的生成；再经减压蒸发和加碱中和,有效去除糖液中的低沸点有机酸和酯类发酵抑制物；然后利用活性炭和双氧水联合处理,能在糖损失极低的情况下,有效的去除发酵抑制物糠醛,糖浓缩液中糖损失小于1g/L,糠醛的脱除达到85％～95％,显著提升了乙醇发酵速率和产率,为白酒丢糟提供了更为高效的利用方法。(The invention discloses a method for improving the yield of ethanol prepared from distilled spirit distiller grains, and belongs to the field of agricultural and sideline product recycling. The invention provides a method for improving the yield of ethanol prepared by distilling white spirit grains, which aims to improve the utilization rate of the white spirit grains and improve the yield of ethanol fermentation, and the method firstly adjusts the humidity of the white spirit grains, and then adopts mild hydrolysis of dilute acid to ensure higher reducing sugar yield and reduce the generation of fermentation inhibitors; then, the low-boiling organic acid and ester fermentation inhibitors in the sugar solution are effectively removed through reduced pressure evaporation and alkali addition neutralization; and then, the active carbon and hydrogen peroxide are used for combined treatment, so that the fermentation inhibitor furfural can be effectively removed under the condition of extremely low sugar loss, the sugar loss in the sugar concentrated solution is less than 1g/L, the removal rate of furfural reaches 85% -95%, the ethanol fermentation rate and the yield are remarkably improved, and a more efficient utilization method is provided for the white spirit waste lees.)
1. The method for improving the yield of ethanol prepared from the distilled spirit distiller grains is characterized by comprising the following steps: the method comprises the following steps:
A. soaking: regulating the humidity of the liquor loss grains to 55-60% of water content mass fraction;
B. degradation and saccharification: mixing the soaked distilled spirit waste lees with dilute acid, hydrolyzing and saccharifying, and then carrying out solid-liquid separation to obtain acidic dilute sugar solution;
C. concentration: concentrating the acidic dilute sugar solution at the temperature of 50-55 ℃ until the concentration of reducing sugar is 60-65 g/L to obtain sugar concentrated solution;
D. neutralizing: adjusting the pH of the sugar concentrated solution to 4.0-4.5;
E. removing furfural: mixing the sugar concentrated solution with adjusted pH with active carbon and hydrogen peroxide, shaking, adding catalase, and separating to obtain sugar purified solution;
F. fermentation: inoculating yeast seed liquid into the sugar purification liquid, adding peptone, yeast extract, magnesium sulfate heptahydrate and diammonium hydrogen phosphate, and fermenting to obtain ethanol.
2. The method of claim 1, wherein the method for improving the yield of ethanol produced from distilled spirit grains comprises: in the step B, at least one of the following items is satisfied:
the dilute acid is H+Inorganic acid with the concentration of 0.2-0.5 mol/L;
the dilute acid is at least one of sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid;
preferably, the dilute acid is sulfuric acid.
3. The method of claim 1 or 2, wherein the method for promoting the yield of ethanol distilled from distilled grains comprises: in the step B, the mass ratio of the soaked white spirit waste lees to the dilute acid is 1: 4 to 5.
4. The method of claim 1, wherein the method for improving the yield of ethanol produced from distilled spirit grains comprises: in the step B, the temperature of the hydrolytic saccharification is 120-125 ℃; in the step B, the time for hydrolysis and saccharification is 20-30 min.
5. The method of claim 1, wherein the method for improving the yield of ethanol produced from distilled spirit grains comprises: in step D, CaO and CaOH are adopted2、CaCO3NaOH or Na2CO3Adjusting the pH.
6. The method of claim 1, wherein the method for improving the yield of ethanol produced from distilled spirit grains comprises: in the step E, the ratio of the mass of the activated carbon to the volume of the sugar concentrated solution is 2-3 percent; the ratio of the volume of the hydrogen peroxide to the volume of the sugar concentrated solution is 1.5-2%.
7. The method of claim 1, wherein the method for improving the yield of ethanol produced from distilled spirit grains comprises: in the step E, the oscillation frequency is 120-180R/min; the oscillation time is 30-60 min.
8. The method of claim 1, wherein the method for improving the yield of ethanol produced from distilled spirit grains comprises: in the step F, the inoculation amount of the yeast seed liquid is 8-10%.
9. The method of claim 1, wherein the method for improving the yield of ethanol produced from distilled spirit grains comprises: in the step F, the addition amount of the peptone is 0.4-0.6/L of sugar purification liquid; the addition amount of the yeast extract is 0.3-0.7 g/L of sugar purification liquid; the adding amount of the magnesium sulfate heptahydrate is 0.1-0.15 g/L of the sugar purification solution; the adding amount of the diammonium hydrogen phosphate is 0.2-0.3 g/L of the sugar purification liquid.
10. The method for promoting distilled spirit loss according to any one of claims 1 to 9, wherein the method comprises the following steps: in the step F, the fermentation is constant-temperature fermentation, and the fermentation temperature is 28-30 ℃.
Technical Field
The invention belongs to the technical field of agricultural and sideline product recycling, and particularly relates to a method for improving the yield of ethanol prepared from distilled spirit distiller grains.
Background
China's liquor-making distiller grains are main by-products of solid-state liquor making, and about 3 tons of distiller grains are generated every 1 ton of liquor according to the solid-state liquor production process. Statistically, during the period from 2015 to 2019, the annual average yield of the national white spirit is 971.6 ten thousand kiloliters, about 3000 million tons of the distilled grains are produced, and along with gradual warming of the industrial policy of the white spirit and upgrading and transformation of the yield of each large distilled grain, the yield of the distilled grains is increased year by year. Such huge wine loss grains can cause environmental pollution and waste of resources if the huge wine loss grains are directly discharged into the environment without reasonable treatment. In recent years, a series of researches are carried out by numerous scholars on the way that the liquor-brewing distilled grains are used as feed additives, fertilizer production, energy utilization, charcoal development and the like, but the liquor-brewing distilled grains have the characteristics of high water content, large residual amount of lactic acid and acetic acid, easiness in mildew formation, difficult rancidity and desiccation and the like, and the application of the liquor-brewing distilled grains as the feed additives, the fertilizer production and the energy development is greatly limited.
The wine distilling grains contain 65-70% of total carbohydrate including starch, cellulose, hemicellulose and the like, and can degrade polysaccharide through treatment to serve as a good carbon source for microbial fermentation. Acid hydrolysis is a commonly used biomass high-efficiency degradation saccharification method, and sulfuric acid, maleic acid, hydrochloric acid, nitric acid and phosphoric acid are generally used as catalysts. Lignocellulose at higher temperatures and H+At a concentration, hexoses such as glucose, galactose, and mannose, and pentoses such as xylose and arabinose are mainly produced, but at a higher temperature and a higher hydrogen ion concentration, pentoses are highly likely to undergo side reactions, and fermentation inhibitors such as furfural, 5-Hydroxymethylfurfural (HMF), and Levulinic Acid (LA) are produced in large amounts. Therefore, the high-temperature acid hydrolysis saccharification process of the wine distiller grains needs to be efficiently hydrolyzedConverting the furfural into reducing sugar to be used as a carbon source for microbial fermentation, and considering to reduce the generation of furfural fermentation inhibitors as much as possible. Reports indicate that the adaptability of fermentation bacteria and fungi to furfural is enhanced in the last decade, but when the furfural concentration is more than 0.6g/L, a remarkable inhibiting effect is generated on the fermentation of some bacteria and fungi.
Renhai Wei et al reported optimization of the spent grain saccharification conditions of white spirit and ethanol fermentation (application and environmental biology reports, 2013, 19 (5): 838-844), and research showed that at the temperature of 100 ℃, the solid-to-liquid ratio is 1:12, the concentration of mixed acid is 2.5%, the hydrolysis time is 120min, the concentration of reducing sugar in the hydrolysis liquid is 59.32g/L under the conditions, the conversion rates of hemicellulose and cellulose in the acidolysis stage are 77.38% and 62.50%, the dissolution rate of lignin is 43.50%, and the generation amount of furfural is 8.37 g/L.
The research on the production of fuel alcohol by saccharifying and degrading the white spirit waste lees by the concentrated sulfuric acid (research on the production of fuel alcohol by saccharifying and degrading the white spirit waste lees by the concentrated sulfuric acid, proceedings of the academic society of the national environmental science institute, 2012, 2458 and 2463), the sugar recovery rate of the white spirit waste lees can reach 79.0 percent after the white spirit waste lees are saccharified and degraded by the concentrated sulfuric acid, and the ethanol concentration and the yield can reach 31.3-34.8 g/L and 81.5-90.7 percent after continuous alcohol fermentation by using flocculating yeast.
However, the above documents only relate to the processes from pretreatment to saccharification degradation and ethanol fermentation of spent grains of white spirit, and do not relate to the processes of controlling and removing fermentation inhibitors such as furfural and oxalic acid in degraded sugar solution, so as to improve the ethanol fermentation yield, and waste biomass resources of agricultural and sideline products are not fully utilized.
Disclosure of Invention
The invention aims to provide a method for removing fermentation inhibitors in distilled spirit distilled grain acidolysis sugar liquor so as to improve the yield of ethanol fermentation, and is characterized in that the distilled spirit distilled grain is mildly degraded by dilute acid, the fermentation inhibitors in saccharified liquor are removed, and the fermentable sugar liquor highly converted into ethanol is obtained.
Specifically, the invention provides a method for improving the yield of ethanol prepared from distilled spirit distiller grains, which comprises the following steps:
A. soaking: regulating the humidity of the liquor loss grains to 55-60% of water content mass fraction;
B. degradation and saccharification: mixing the soaked distilled spirit waste lees with dilute acid, hydrolyzing and saccharifying, and then carrying out solid-liquid separation to obtain acidic dilute sugar solution;
C. concentration: concentrating the acidic dilute sugar solution at the temperature of 50-55 ℃ until the concentration of reducing sugar is 60-65 g/L to obtain sugar concentrated solution;
D. neutralizing: adjusting the pH of the sugar concentrated solution to 4.0-4.5;
E. removing furfural: mixing the sugar concentrated solution with adjusted pH with active carbon and hydrogen peroxide, shaking, adding catalase, and separating to obtain sugar purified solution;
F. fermentation: inoculating yeast seed liquid into the sugar purification liquid, adding peptone, yeast extract, magnesium sulfate heptahydrate and diammonium hydrogen phosphate, and fermenting to obtain ethanol.
In the step B, the dilute acid is H+Inorganic acid with the concentration of 0.2-0.5 mol/L.
In the method for improving the yield of the ethanol prepared from the distilled spirit distiller grains, in the step B, the dilute acid is at least one of sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid.
Preferably, in the step B, the dilute acid is sulfuric acid.
In the method for improving the yield of the ethanol prepared from the distilled grain distilled from the white spirit, in the step B, the mass ratio of the soaked distilled grain distilled from the white spirit to the dilute acid is 1: 4 to 5.
In the method for improving the yield of the ethanol prepared from the distilled spirit distiller grains, in the step B, the temperature of hydrolysis and saccharification is 120-125 ℃.
In the method for improving the yield of the ethanol prepared from the distilled spirit distiller grains, in the step B, the hydrolysis saccharification time is 20-30 min.
Wherein, in the step D, CaO and CaOH are adopted to improve the yield of the ethanol prepared from the distilled spirit distiller grains2、CaCO3NaOH or Na2CO3Adjusting the pH.
In the method for improving the yield of the ethanol prepared from the distilled spirit distiller grains, in the step E, the ratio of the mass of the activated carbon to the volume of the sugar concentrated solution is 2-3%.
In the method for improving the yield of the ethanol prepared by the distilled spirit distiller, in the step E, the volume ratio of the hydrogen peroxide to the sugar concentrated solution is 1.5-2%.
In the method for improving the yield of the ethanol prepared from the distilled spirit distiller grains, in the step E, the oscillation frequency is 120-180R/min.
In the method for improving the yield of the ethanol prepared from the distilled spirit distiller grains, in the step E, the shaking time is 30-60 min.
In the method for improving the yield of the ethanol prepared from the distilled spirit distiller grains, in the step F, the inoculation amount of the yeast seed liquid is 10-15%.
In the method for improving the yield of the ethanol prepared by the distilled spirit distiller, in the step F, the addition amount of the peptone is 0.4-0.6/L of sugar purified liquid; the addition amount of the yeast extract is 0.3-0.7 g/L of sugar purification liquid; the adding amount of the magnesium sulfate heptahydrate is 0.1-0.15 g/L of the sugar purification solution; the adding amount of the diammonium hydrogen phosphate is 0.2-0.3 g/L of the sugar purification liquid.
In the method for improving the ethanol yield of the distilled spirit distiller's grains, in the step F, the fermentation is constant-temperature fermentation, and the fermentation temperature is 28-30 ℃.
The invention has the following effects:
the invention firstly adjusts the humidity of the distilled grain of the distilled spirit, makes the distilled grain have uniform components, is beneficial to the stability of the subsequent acidolysis saccharification process, and then adopts dilute acid for mild hydrolysis (lower H)+Concentration and proper temperature), thereby remarkably reducing the generation of fermentation inhibitors such as furfural and the like on the premise of ensuring higher yield of reducing sugar; then the diluted sugar solution is decompressed and evaporated and then is neutralized by adding alkali, so that low-boiling organic acid and ester fermentation inhibitors in the sugar solution can be effectively removed; then the active carbon and hydrogen peroxide are used for combined treatment, so that the fermentation inhibitor furfural can be effectively removed under the condition of extremely low sugar loss, and the sugar loss in the sugar concentrated solutionLess than 1g/L, the removal of furfural reaches 85-95%, and a foundation is provided for subsequent high-efficiency fermentation and transformation, so that the ethanol fermentation rate and yield are remarkably improved, and a more efficient utilization method is provided for the white spirit waste lees.
Detailed Description
Specifically, the method for improving the yield of ethanol prepared from distilled spirit distiller grains comprises the following steps:
A. soaking: regulating the humidity of the liquor loss grains to 55-60% of water content mass fraction;
B. degradation and saccharification: mixing the soaked distilled spirit waste lees with dilute acid, hydrolyzing and saccharifying, and then carrying out solid-liquid separation to obtain acidic dilute sugar solution;
C. concentration: concentrating the acidic dilute sugar solution at the temperature of 50-55 ℃ until the concentration of reducing sugar is 60-65 g/L to obtain sugar concentrated solution;
D. neutralizing: adjusting the pH of the sugar concentrated solution to 4.0-4.5;
E. removing furfural: mixing the sugar concentrated solution with adjusted pH with active carbon and hydrogen peroxide, shaking, adding catalase, and separating to obtain sugar purified solution;
F. fermentation: inoculating yeast seed liquid into the sugar purification liquid, adding peptone, yeast extract, magnesium sulfate heptahydrate and diammonium hydrogen phosphate, and fermenting to obtain ethanol.
The yield of the Luzhou-flavor liquor accounts for more than 70% of the liquor yield, the invention mainly considers the treatment process of the Luzhou-flavor liquor lost grains, and other lost grains are also suitable for the method. Due to source difference of the white spirit lost grains caused by different production process routes of the strong aromatic white spirit, the initial water content mass fraction of the white spirit lost grains is different from 40% to 60%, although the water content is high or low, if the water content is too high or too low, the change of the proportion of the white spirit lost grains to the acid liquor in the degradation and saccharification processes can be influenced, the process is unstable, and the industrial production is not facilitated, so that in the step A of the method, the humidity of the white spirit lost grains is adjusted to 55% to 60%, the humidity of the white spirit lost grains is consistent, the components are uniform, and the stability of a subsequent acidolysis saccharification process is facilitated.
Through tests, step B of the method of the inventionIn, use H+Inorganic acid with the concentration of 0.2-0.5 mol/L, and controlling the mass ratio of the waste lees of the soaked white spirit to the dilute acid to be 1: 4-5, and hydrolyzing and saccharifying at 120-125 ℃ for 20-30 min, so that fermentation inhibitors such as furfural can be reduced, and the sugar yield can be improved; wherein the dilute acid can be at least one of sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid; preferably sulfuric acid. In the step B, the hydrolysis saccharification can be carried out by adopting a container (such as a reaction kettle) which can meet the acidolysis condition; the solid-liquid separation can be carried out by adopting modes such as filter pressing or continuous centrifugation.
In the step C of the method, the acidic dilute sugar solution is concentrated until the concentration of reducing sugar is 60-65 g/L, so that the fermentation rate of ethanol can be remarkably increased, and the conversion rate of ethanol can be higher; the concentration is low, which is not beneficial to the rapid establishment of the strain advantages and the rapid propagation of the strains; too high a concentration may cause a change in the osmotic pressure of the microbial cells, which is detrimental to fermentation.
In the step D of the method, the pH value of the sugar concentrated solution is adjusted to 4.0-4.5, and the pH value can ensure the subsequent furfural removing effect; if the pH value is higher or lower, the subsequent removal of furfural by the combination of active carbon and hydrogen peroxide is not facilitated. In step D, CaO and CaOH can be adopted2、CaCO3NaOH or Na2CO3Adjusting the pH.
In the step E of the method, active carbon and hydrogen peroxide are jointly treated, so that the fermentation inhibitor furfural can be effectively removed under the condition of extremely low sugar loss. Tests show that the ratio of the mass of the activated carbon to the volume of the sugar concentrated solution is controlled to be 2-3%, and the ratio of the volume of the hydrogen peroxide to the volume of the sugar concentrated solution is controlled to be 1.5-2%, so that most fermentation inhibitors such as furfural and the like can be removed under the condition of reducing sugar loss as much as possible. In the step E, the activated carbon and the hydrogen peroxide can adopt conventional commercial products; wherein, the concentration of the hydrogen peroxide sold in market is generally 30%, the volume of the hydrogen peroxide is calculated according to 30% of the hydrogen peroxide, but the rest concentration (not less than 10%) of the hydrogen peroxide is also suitable for the method, and the method is carried out according to the H in the system2O2Under the condition of unchanged content, the conversion is carried out according to 30 percent hydrogen peroxide.
In the step E of the method, after adding activated carbon and hydrogen peroxide, oscillating for 30-60 min at 120-180R/min, then adding sufficient hydrogen peroxide enzyme liquid (the dosage is generally more than 2% of the volume proportion of the sugar concentrated liquid) to decompose residual hydrogen peroxide in the sugar concentrated liquid, and then separating to finish the removal of fermentation inhibitors such as furfural and the like.
In step F of the method of the present invention, the ethanol fermentation process is a mature prior art, and yeasts and culture media for ethanol fermentation are common knowledge in the art. In the step F, the inoculation amount of the yeast seed liquid is 10-15%; the addition amount of the peptone is 0.4-0.6/L (before inoculation) of the sugar purification liquid, the addition amount of the yeast extract is 0.3-0.7 g/L (before inoculation) of the sugar purification liquid, the addition amount of the magnesium sulfate heptahydrate is 0.1-0.15 g/L (before inoculation) of the sugar purification liquid, and the addition amount of the diammonium phosphate is 0.2-0.3 g/L (before inoculation) of the sugar purification liquid; the fermentation is constant-temperature fermentation, and the fermentation temperature is 28-30 ℃.
The present invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.
Example 1
The white spirit waste lees used in the embodiment are the lees obtained after solid fermentation of strong aromatic white spirit, and the process comprises the following steps:
A. the lost grain is wetted: collecting the liquor distiller grains, and adjusting the humidity of the liquor distiller grains to 55 percent of water content;
B. mild degradation and saccharification of dilute sulfuric acid: taking the waste lees and H of white spirit+Diluted acid solution with the concentration of 0.2mol/L, according to the proportion of 1: 4, fully mixing in a mass ratio, and hydrolyzing and saccharifying for 20min in a reaction kettle at the temperature of 120 ℃; carrying out solid-liquid separation on the cooled acidolysis sugar solution in a filter pressing or continuous centrifugation mode and the like to obtain an acidic dilute sugar solution;
C. and (3) concentrating the dilute sugar solution: decompressing and evaporating the acidic dilute sugar solution at the temperature of 50-55 ℃ until the concentration of reducing sugar is 60g/L, thus obtaining sugar concentrated solution;
D. neutralization of the sugar concentrate: with CaO or CaOH2Adjusting the pH of the hydrolyzed sugar solution to 4.0;
E. removing furfural in the sugar concentrated solution: adding powdered activated carbon accounting for 2 percent (mass to volume ratio) of the sugar concentrated solution and hydrogen peroxide (30 percent concentration) accounting for 1.5 percent (volume to volume ratio) of the sugar concentrated solution at room temperature, oscillating for 30min in a shaking table at 150R/min, adding sufficient hydrogen peroxide enzyme solution to decompose residual hydrogen peroxide in the sugar concentrated solution, stirring, and filtering to obtain sugar purified solution;
F. ethanol fermentation: inoculating 10% of the purified sugar solution into yeast seed solution, adding peptone 0.5g/L, yeast extract 0.5g/L, magnesium sulfate heptahydrate 0.1g/L and diammonium phosphate 0.2g/L, and fermenting at 30 deg.C;
and (4) checking: the furfural content in the sugar concentrated solution was 1.5g/L, and ethanol fermentation was directly carried out for 72h with an ethanol yield of 40g/L and a yield of 66.7%.
After the combined treatment of the activated carbon and the hydrogen peroxide, the sugar loss in the sugar concentrated solution is less than 1g/L, the furfural removal rate reaches 87.2%, the optimal fermentation time of ethanol is 60h, the ethanol yield is 48g/L, the yield is 80%, and the ethanol fermentation rate and the yield are remarkably improved.
Example 2
The white spirit waste lees used in the embodiment are the lees obtained after solid fermentation of strong aromatic white spirit, and the process comprises the following steps:
A. the lost grain is wetted: collecting the liquor distiller grains, and adjusting the humidity of the liquor distiller grains to 60 percent;
B. mild degradation and saccharification of dilute sulfuric acid: taking the waste lees and H of white spirit+Diluted acid solution with concentration of 0.5mol/L, according to the proportion of 1: 5, fully mixing the components in a mass ratio, and hydrolyzing and saccharifying the mixture for 30min in a reaction kettle at the temperature of 125 ℃; carrying out solid-liquid separation on the cooled acidolysis sugar solution in a filter pressing or continuous centrifugation mode and the like to obtain an acidic dilute sugar solution;
C. and (3) concentrating the dilute sugar solution: decompressing and evaporating the acidic dilute sugar solution at the temperature of 50-55 ℃ until the concentration of reducing sugar is 65g/L, thus obtaining sugar concentrated solution;
D. neutralization of the sugar concentrate: with CaO or CaOH2Adjusting the pH of the hydrolyzed sugar solution to 4.5;
E. removing furfural in the sugar concentrated solution: adding powdered activated carbon accounting for 3 percent (mass to volume ratio) of the sugar concentrated solution and hydrogen peroxide (30 percent concentration) accounting for 2 percent (volume to volume ratio) of the sugar concentrated solution at room temperature, oscillating for 30min in a shaking table at 150R/min, adding sufficient hydrogen peroxide enzyme solution to decompose residual hydrogen peroxide in the sugar concentrated solution, stirring, and filtering to obtain sugar purified solution;
F. ethanol fermentation: inoculating 10% of the purified sugar solution into yeast seed solution, adding peptone 0.5g/L, yeast extract 0.5g/L, magnesium sulfate heptahydrate 0.1g/L and diammonium phosphate 0.2g/L, and fermenting at 30 deg.C;
and (4) checking: the furfural content in the sugar concentrated solution is 1.9g/L, ethanol fermentation is directly carried out, the fermentation time is 72h, the ethanol yield is 39g/L, and the yield is 60%;
after the active carbon and hydrogen peroxide are combined for treatment, the sugar loss in the sugar concentrated solution is less than 1g/L, the removal of furfural reaches 93.2%, the optimal fermentation time of ethanol is 60h, the yield of ethanol is 46g/L, the yield is 71%, and the fermentation rate and the yield of ethanol are remarkably improved.
Example 3
The white spirit waste lees used in the embodiment are the lees obtained after solid fermentation of strong aromatic white spirit, and the process comprises the following steps:
A. the lost grain is wetted: collecting the liquor distiller grains, and adjusting the humidity of the liquor distiller grains to 60 percent;
B. mild degradation and saccharification of dilute sulfuric acid: taking the waste lees and H of white spirit+Diluted acid solution with concentration of 0.5mol/L, according to the proportion of 1: 5, fully mixing the components in a mass ratio, and hydrolyzing and saccharifying the mixture for 20min in a reaction kettle at the temperature of 125 ℃; carrying out solid-liquid separation on the cooled acidolysis sugar solution in a filter pressing or continuous centrifugation mode and the like to obtain an acidic dilute sugar solution;
C. and (3) concentrating the dilute sugar solution: decompressing and evaporating the acidic dilute sugar solution at the temperature of 50-55 ℃ until the concentration of reducing sugar is 60g/L, thus obtaining sugar concentrated solution;
D. neutralization of the sugar concentrate: with CaO or CaOH2Adjusting the pH of the hydrolyzed sugar solution to 4.0;
E. removing furfural in the sugar concentrated solution: adding powdered activated carbon accounting for 3 percent (mass to volume ratio) of the sugar concentrated solution and hydrogen peroxide (30 percent concentration) accounting for 1.8 percent (volume to volume ratio) of the sugar concentrated solution at room temperature, oscillating for 30min in a shaking table at 150R/min, adding sufficient hydrogen peroxide enzyme solution to decompose residual hydrogen peroxide in the sugar concentrated solution, stirring, and filtering to obtain sugar purified solution;
F. ethanol fermentation: inoculating 10% of the purified sugar solution into yeast seed solution, adding peptone 0.5g/L, yeast extract 0.5g/L, magnesium sulfate heptahydrate 0.1g/L and diammonium phosphate 0.2g/L, and fermenting at 30 deg.C;
and (4) checking: the furfural content in the sugar concentrated solution is 1.7g/L, ethanol fermentation is directly carried out, the optimal fermentation time is 72h, the ethanol yield is 43g/L, and the yield is 71.6%;
after the active carbon and hydrogen peroxide are combined for treatment, the sugar loss in the sugar concentrated solution is less than 1g/L, the removal of furfural reaches 94.1%, the optimal fermentation time of ethanol is 60h, the yield of ethanol is 51g/L, the yield is 85%, and the fermentation rate and the yield of ethanol are remarkably improved.