Method for producing ethanol by co-fermentation of glucose and xylose

Abstract

The invention belongs to the technical field of cellulosic ethanol production, and particularly relates to a method for producing ethanol by co-fermentation of glucose and xylose. The method comprises the following steps of: (1) strain selection; (2) slant culture; (3) seed culture; (4) seed expanding culture; (5) fermentation culture; and (6) distillation of the fermentation liquid obtained in the step (5) to obtain ethanol. By using the material enzymolysis liquid obtained by the widely used steam explosion pretreatment technique as the culture medium, on the basis of directional stress resistance and fermentation property domestication of the pentose yeast strain, the strain is utilized to perform ethanol fermentation; and in the high-concentration acetic acid and furfural environment, the glucose and xylose are synchronously fermented to produce ethanol, so that the glucose utilization ratio is up to 99.5% or above, the xylose utilization ratio is up to 70% or above, the ethanol yield is up to 85% of the theoretical value, and the raw material utilization ratio and ethanol yield are effectively enhanced.

Description

technical field [0001] The invention belongs to the technical field of cellulosic ethanol production, and in particular relates to a method for co-fermenting glucose and xylose to produce ethanol. Background technique [0002] With the emphasis on environmental protection and effective utilization of renewable resources, the development of renewable energy has become a global consensus. As the world's second largest energy consumer, my country's energy structure is dominated by coal, and the extensive use of fossil fuels has caused enormous pressure on the environment. Vigorously developing renewable energy can alleviate the pressure on the environment to a certain extent. According to reports, the world's annual straw production is about 2.9 billion tons, of which corn straw accounts for 35%, wheat straw accounts for 21%, and rice straw accounts for 19%. 66% of the world's crop straws are directly returned to the field or burned as living energy, which not only causes ener...

AI Technical Summary

Problems solved by technology

[0003] Cellulosic raw materials, especially lignocellulose, are mainly composed of three major types of substances: cellulose, hemicellulose, and lignin, and the contents of the three are roughly 30-40%, 20-30%, and 10-25% respectively; In the process of producing ethanol from cellulosic raw materials, glucose, the product of cellulose hydrolysis, is most widely used, while xylose and arabinose produced by hydrolysis of hemicellulose are less utilized, mainly because the traditional ethanol fermentation strain is Saccharomyces cerevisiae and its ethanol tolerance strong, high yield, and strong resistance to inhibitors in the cellulosic raw material hydrolyzate, but it cannot ferment xylose to produce ethanol, resulting in low raw material utilization and low ethanol yield, which increases the production cost of cellulosic ethanol accordingly