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CN-115820750-B - Method for producing ethanol by enzymolysis and fermentation of poplar and application thereof

CN115820750BCN 115820750 BCN115820750 BCN 115820750BCN-115820750-B

Abstract

The invention discloses a method for producing ethanol by enzymolysis and fermentation of poplar, which comprises the steps of firstly pretreating poplar by adopting metal chloride and ethanol aqueous solution, and then carrying out synchronous saccharification and fermentation on pretreated poplar to produce ethanol, wherein the metal chloride is aluminum chloride and/or chromium chloride. The method is used for preprocessing poplar and then carrying out synchronous saccharification and fermentation, when the substrate concentration of the poplar is 30%, the yield of glucose produced by enzymolysis of the poplar can reach 62.28g/L, and when the substrate concentration of the poplar is 32%, the yield of glucose produced by enzymolysis of the poplar can reach 64.85g/L. Under the condition of effectively removing lignin, the method can also improve the reactivity of cellulase, effectively improve the efficiency of enzymolysis and fermentation of poplar and improve the yield of ethanol.

Inventors

  • Fan Meishan
  • XIE JUN
  • ZHANG HONGDAN

Assignees

  • 华南农业大学

Dates

Publication Date
20260508
Application Date
20221208

Claims (5)

  1. 1. The method for producing the ethanol by fermenting the poplar through enzymolysis is characterized by comprising the following steps of: S1, poplar pretreatment, namely mixing crushed poplar, chromium chloride and ethanol water solution to obtain mixed solution, reacting for 10-35 min at 160-200 ℃, and collecting filter residues through solid-liquid separation; the mass volume ratio of the crushed poplar to the ethanol water solution is 1g to 15 mL, the volume concentration of the ethanol water solution is 30%, and the final concentration of the chromium chloride in the mixed solution is 0.025mol/L; s2, mixing the filter residue obtained in the step S1, cellulase, saccharomycete activating solution and nutrient solution to obtain fermentation liquor, and carrying out saccharification and fermentation on the fermentation liquor to obtain ethanol; The nutrient solution comprises 1~3 g:0.5~1.5 g:0.5~1.5 g:0.1~0.5 g:1L mass-volume ratio of yeast extract, ammonium chloride, potassium dihydrogen phosphate, magnesium sulfate and water, the saccharification and fermentation temperature is 30-38 ℃, the mass-volume ratio of filter residues obtained in the step S1 to fermentation solution is 32 g/100 mL, the dosage ratio of the filter residues obtained in the step S1 to cellulase is 1 g/10 FPU, and the concentration of saccharomycetes in the fermentation solution is 3.33g/L.
  2. 2. The method according to claim 1, wherein the solid-liquid separation in step S1 is vacuum filtration separation and/or centrifugation.
  3. 3. The method according to claim 1, wherein the yeast activation solution in step S2 is a saccharomyces cerevisiae activation solution.
  4. 4. The method according to claim 1, wherein the nutrient solution in step S2 is composed of yeast extract, ammonium chloride, potassium dihydrogen phosphate, magnesium sulfate and water in a mass-to-volume ratio of 2 g:1 g:1 g:0.3 g:1L.
  5. 5. The use of the method according to any one of claims 1 to 4 for increasing the efficiency of ethanol production by enzymatic hydrolysis of poplar.

Description

Method for producing ethanol by enzymolysis and fermentation of poplar and application thereof Technical Field The invention relates to the technical field of ethanol preparation, in particular to a method for producing ethanol by enzymolysis and fermentation of poplar and application thereof. Background The problems of increasingly exhausted fossil resources, environmental pollution and the like are strong power for developing lignocellulose biomass resource conversion. Lignocellulosic biomass has been developed as a promising rich resource for the production of sustainable alternatives (biofuels, chemicals and materials) from its main components, providing a sustainable way to alleviate long-term energy safety requirements. The poplar is rich in resources, is an important raw material for producing bioenergy and biomass chemicals, and has great potential for preparing bioenergy and chemicals by bioconversion of poplar. However, because the cellulose, hemicellulose and lignin in poplar are tightly connected together, the structure is stable and is not easy to be destroyed by cellulase. In general, in the production of bioethanol, glucose is first released from lignocellulose by hydrolyzing cellulose with cellulase, and then bioethanol is obtained by fermenting monosaccharides (glucose) with yeast. However, the refractory structure of biomass still limits the efficiency of cellulose conversion to glucose. It is therefore necessary to pretreat biomass resources as they are being converted. The pretreatment methods currently used include acid pretreatment, alkali pretreatment, organic solvent pretreatment and ionic liquid pretreatment. The organic solvent method is attracting attention because it can fully dissolve lignin, produce solid materials with stronger reactivity, and the solvent is easy to realize recycling. The addition of an acidic or basic catalyst to the organic solvent can further cleave the heterocyclic ether linkage between the polysaccharides, releasing the monosaccharides, resulting in a digestible cellulose-rich substrate. However, high concentrations of mineral acids degrade xylose in lignin to produce fermented plants such as furfural while destroying part of the cellulose, which is detrimental to the full component biorefinery of the feedstock (wood). Therefore, a method for effectively improving the enzymolysis and fermentation efficiency of poplar is needed. Disclosure of Invention The invention aims to overcome the defects in the prior art and provides a method for producing ethanol by enzymolysis and fermentation of poplar and application thereof. The first object of the invention is to provide a method for producing ethanol by enzymolysis and fermentation of poplar. A second object of the present invention is to provide the use of the above method for increasing the efficiency of ethanol production by enzymatic hydrolysis of poplar. In order to achieve the above object, the present invention is realized by the following means: A method for producing ethanol by enzymolysis and fermentation of poplar comprises the following steps: S1, poplar pretreatment, namely mixing crushed poplar, metal chloride and an ethanol water solution to obtain a mixed solution, reacting for 10-35 min at 160-200 ℃, and collecting filter residues through solid-liquid separation; The mass volume ratio of the crushed poplar to the ethanol aqueous solution is 1 g:8-15 mL, the volume concentration of the ethanol aqueous solution is 30% -80%, the final concentration of the metal chloride in the mixed solution is 0.01-0.03 mol/L, and the metal chloride is aluminum chloride and/or chromium chloride; s2, mixing the filter residue obtained in the step S1, cellulase, saccharomycete activating solution and nutrient solution to obtain fermentation liquor, and carrying out saccharification and fermentation on the fermentation liquor to obtain ethanol; The nutrient solution comprises 1-3 g of yeast extract, 0.5-1.5 g of ammonium chloride, 0.1-0.5 g of monopotassium phosphate, magnesium sulfate and water in a mass-volume ratio of 1-3 g to 0.5g to 0.1-0.5 g to 1L, wherein the temperature of saccharification and fermentation is 30-38 ℃, the mass-volume ratio of filter residues obtained in the step S1 to fermentation broth is 10-32 g to 100mL, the dosage ratio of filter residues obtained in the step S1 to cellulase is 1g to 10-30 FPU, and the concentration of saccharomycetes in the fermentation broth is 1-5 g/L. Preferably, in the step S1, the crushed poplar is 20-60 meshes of poplar. Preferably, the mass-to-volume ratio of the crushed poplar to the ethanol aqueous solution in the step S1 is 1g to 10mL. Preferably, the metal chloride in step S1 is chromium chloride. More preferably, the final concentration of the chromium chloride in the mixed liquor is 0.025mol/L. Preferably, the volume concentration of the aqueous ethanol solution is 60%. Preferably, the solid-liquid separation in step S1 is vacuum filtration separation and