PROCESS COMPRISING SULFUR DIOXIDE AND/OR SULFUROUS ACID PRETREATMENT AND ENZYMATIC HYDROLYSIS

摘要

The present invention provides a process for producing a fermentation product from a lignocellulosic feedstock. The process comprises soaking a lignocellulosic feedstock in an aqueous solution to produce a soaked feedstock. The soaked feedstock is at least partially dewatered and the at least partially dewatered feedstock is subjected to pretreating in the presence of sulfur dioxide, sulfurous acid or a combination thereof to produce a pretreated feedstock composition. The pretreated feedstock composition is fed to an enzymatic hydrolysis in which the concentration of dissolved solids fed to the enzymatic hydrolysis is at least 50% (w/w) of the concentration of dissolved solids in the pretreated feedstock composition. The cellulose in the pretreated feedstock composition is hydrolyzed with cellulase enzymes in the presence of the dissolved solids to produce glucose. The glucose is fermented to produce the fermentation product.