Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 17, 2002
Publication Date: N/A
Technical Abstract: Corn fiber, a by-product of corn wet milling industry, can serve as a low cost feedstock for production of fuel ethanol and other value-added fermentation products. Currently, enzymatic saccharification of corn fiber to fermentable sugars faces significant technical and economic challenges. Its success depends largely on the development of environmentally friendly pretreatment procedures and highly effective enzyme systems for conversion of pretreated corn fiber to fermentable sugars. Several pretreatments (hot water, alkali, and dilute acid) and enzymatic saccharification procedures were evaluated for conversion of corn fiber starch, cellulose, and hemicellulose to fermentable sugars. The structure of corn fiber heteroxylan is very complex, and commercially available hemicellulase preparations do not effectively hydrolyze it to simple sugars. Based on these findings, a method of dilute acid pretreatment (0.5% H2SO4, v/v, 121 deg C, 1 h) of corn fiber (15%, w/v) and saccharification (45 deg C, pH 5.0, 72 h) with commercial cellulase and beta-glucosidase preparations is presented. The yield of monomeric sugars from corn fiber was typically 85-100% of the theoretical yield. Currently, the cost of cellulase enzymes is 50 cents per gallon of ethanol produced from pretreated corn fiber substrate. Research emphasis is being directed towards lowering the cellulase enzyme cost by a factor of 10. Our progress in research on the development of several novel enzymes for cellulose and hemicellulose conversion will be described. The prospects of using enzymes in corn fiber saccharification commercially and economic assessment will be discussed.