Pretreatment and enzymatic saccharification of corn fiber

Corn fiber consists of about 20% starch, 14% cellulose, and 35% hemicellulo se, and has the potential to serve as a low-cost feedstock for production o f fuel ethanol. Several pretreatments (hot water, alkali, and dilute acid) and enzymatic saccharification procedures were evaluated for the conversion of corn fiber starch, cellulose, and hemicellulose to monomeric sugars. Ho t water pretreatment (121 degrees C, 1 h) facilitated the enzymatic sacchar ification of starch and cellulose but not hemicellulose. Hydrolysis of corn fiber pretreated with alkali under similar conditions by enzymatic means g ave similar results. Hemicellulose and starch components were converted to monomeric sugars by dilute H2SO4 pretreatment (0.5-1.0%, v/v) at 121 degree s C. Based on these findings, a method for pretreatment and enzymatic sacch arification of corn fiber is presented. It involves the pretreatment of cor n fiber (15% solid, w/v) with dilute acid (0.5% H2SO4, v/v) at 121 degrees C for 1 h, neutralization to pH 5.0, then saccharification of the pretreate d corn fiber material with commercial cellulase and P-glucosidase preparati ons. The yield of monomeric sugars from corn fiber was typically 85-100% of the theoretical yield.