METHOD OF PRODUCING BIOETHANOL BY ENZYMATIC HYDROLYSIS OF CELLULOSE Russian patent published in 2016 - IPC C12P7/10 

FIELD: chemistry.

SUBSTANCE: method of producing bioethanol from lignin-cellulose plant material involves pre-treatment of said raw material, enzymatic hydrolysis and alcoholic fermentation of products obtained after hydrolysis, capable of fermentation to produce bioethanol. Pretreatment comprises decomposition of raw material by holding in presence of a mixture containing formic acid and water at 95 °C-110 °C, holding at atmospheric pressure for further separation into a solid phase containing cellulose, and a liquid phase containing mainly a solution consisting of water, formic acid, lignins and hemicelluloses. Prior to enzymatic hydrolysis, method includes partial removal of lignins by treatment with NaOH, followed by washing to remove residual NaOH, to achieve residual total content of lignin (T), other than zero and lying within a range defined by lower (Lnizhn) and upper (Lverh) limits equal to 0.30 wt% and 4 wt%, respectively. Prior to enzymatic hydrolysis, method includes repeated acidification of mixture with acetic acid and/or formic acid and/or citric acid, wherein after repeated acidification pH of mixture is 4-6.

EFFECT: invention provides maximum degree of hydrolysis.

7 cl, 2 dwg, 2 tbl