PROCESS FOR PRODUCING BIOETHANOL BY ENZYMATIC HYDROLYSIS OF CELLULOSE

摘要

The invention concerns a process for producing bioethanol comprising the steps of pretreatment (consisting in destructuring the lignocellulosic vegetable raw material by placing it in the presence of a mixture containing formic acid acetic acid and water then in separating cellulose) of enzymatic hydrolysis and of alcoholic fermentation characterized in that it comprises prior to the enzymatic hydrolysis a step of partial elimination of the lignins so as to obtain a residual overall level of lignins (T) expressed as percentage by weight which is non zero and which is included in a range determined by a lower limit and an upper limit Bsup respectively equal to 0.30% and 4%. In order to obtain conditions of acidification before the enzymatic hydrolysis step the process comprises a step for re acidification of the mixture which is carried out by means of an acid or of a mixture of acids of determined pKa and in particular by means of weak organic acids such as acetic acid and/or formic acid.