US Patent 11008598 Process comprising acid pretreatment and enzymatic hydrolysis

Provided herein is 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. The pretreatment chemical is sulfur dioxide, sulfurous acid or a combination thereof and can be added to the process at any stage prior to and/or during pretreatment. The pretreated feedstock composition is fed to an enzymatic hydrolysis conducted at a temperature that is higher than 58° C. 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.