Copyright © 2005 by Humana Press Inc. All rights of any nature whatsoever reserved. 0273-2289/05/121-124/321-334/$30.00 Profile of Enzyme Production by Trichoderma reesei Grown on Corn Fiber Fractions** XIN-LIANG LI, * BRUCE S. DIEN, MICHAEL A. COTTA, Y. VICTOR Wu, AND BADAL C. SAHA Fermentation Biotechnology Research Unit, National Center for Agricultural Utilization Research, USOAIARS; 1815 N. University Street, Peoria, Illinois 61604, E-mail: lix@ncaur.usda.gov Abstract Com fiber is the fibrous by-product of wet-mill com processing. It typically consists of about 20% starch, 14% cellulose, and 30% hemicellulose in the form of arabinoxylan. Crude com fiber (CCF) was fractionated into de-starched com fiber (DSCF), com fiber with cellulose (CFC) enriched, and com fiber arabi- noxylan (CFAX), and these fractions were evaluated as substrates for enzyme production by Trichodenna reesei. T. reesei QM9414 and Rut C-30 grew on CCF, DSCF, CFC, or CFAX and secreted a number of hydrolytic enzymes. The' enzymes displayed synergism with commercial cellulases for com· fiber hydrolysis. Index Entries: Trichoderma reesei; com fiber; cellulase; xylanase Introduction Fuel ethanol production in the United States has reached an annual level of 2.8 billion gallons using over 900 million bushels of corn. Approximately 50% of com fermented to ethanol is processed by wet- milling. A major by-product of wet milling is corn fiber, an enriched fiber fraction associated with outer hull (periderm). Annual com fiber produc- tion in the US has been estimated at 3.4 million tons (1). Com fiber is cur- rently marketed as a low-grade animal feed ingredient, but market prices have been in decline due to rapid increase in supply. Corn fiber is typically composed of 60-70% carbohydrates, which includes 20% residual starch, 14% cellulose,' and 30% hemicellulose (2). There is an opportunity to reverse this trend by developing alternative uses for com fiber. Corn fiber ""Author to whom all correspondence and reprint requests should be addressed. **Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. #9143 Applied Biochemistry and Biotechnology 321 Vol. 121-124,2005