Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 5, 2005
Publication Date: May 5, 2005
Citation: Dien, B.S., Li, X., Cotta, M.A. 2005. Enzymatic saccharification of pretreated corn fiber for production of sugars [abstract]. Biotechnology for Fuels and Chemicals. Paper No. B-36. Technical Abstract: Corn fiber is a low-value co-product of corn wet milling, which has good potential as a feedstock for ethanol fermentation because of its high carbohydrate content, proximity to existing ethanol facilities, and low-cost. Corn fiber xylan can be easily hydrolyzed by just treating with hot-water. However, fermentation of the resulting hydrolysate is problematic because the yield of simple sugars following saccharification with commercial xylanase preparations is low. To develop more effective enzyme mixtures, both Trichoderma reesei RutC30 and two Aspergillus niger strains were cultured on destarched corn fiber (DSCF) to induce the production of xylanolytic enzyme mixtures. The supernatants were collected and used to saccharify DSCF either alone or in combination with each other. Combining T. reesei Rut C30 with either A. niger preparation increased the yield of xylose and arabinose 180%. The best performing mixture of enzymes was subsequently used to saccharify DSCF that had been treated with 160 deg C water. The heat treatment alone yielded 25% of the xylan as free xylose. Very little of the glucans was converted to glucose. After enzymatic saccharification, 61% of the xylan sugars were released as monomers, as well as much of the glucans (up to 282 mg glucose per g DSCF, db). Current work is directed towards increasing this yield further by optimizing fungal culture conditions, corn fiber pretreatment conditions, evaluating other enzymatic preparations, and adjusting saccharification conditions.