Patent ID: 8318461

Claim:
A process for the enzymatic hydrolysis of cellulose to produce a hydrolysis product comprising glucose from a pretreated lignocellulosic feedstock, the process comprising: (i) providing an aqueous slurry of the pretreated lignocellulosic feedstock, said aqueous slurry comprising fiber solids and an aqueous phase; (ii) hydrolyzing the aqueous slurry with cellulase enzymes that bind to the fiber solids and one or more than one β-glucosidase enzyme having a cellulose binding domain that binds the fiber solids, said hydrolyzing being carried out in a solids-retaining hydrolysis reactor to produce said hydrolysis product comprising glucose; and (iii) withdrawing unhydrolyzed solids and the aqueous phase, which comprises hydrolysis product, from the solids-retaining hydrolysis reactor, wherein the unhydrolyzed fiber solids are retained in the solids-retaining hydrolysis reactor for a mean time of about 6 hours to about 148 hours longer than the aqueous phase.