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Oral
Presentation 3-01 SO2-catalyzed
Steam Explosion of Corn Fiber for Ethanol Production R.
Bura1, R. J. Bothast2,
J. N. Saddler1, and S. D. Mansfield1 1Forest Products Biotechnology Department of Wood Science University of British Columbia Vancouver
B.C. V6T 1Z4 Canada 2Fermentation Biochemistry National Center for Agricultural Utilization Research USDA ARS 1815 N. University St. Peoria IL 61604 Telephone: (604) 822-0196; Fax: (604) 822-9104; E-mail: shawnman@interchange.ubc.ca Corn fiber, a byproduct from the corn wet milling industry, represents a renewable resource that is readily available in significant quantities and could potentially serve as a low cost feedstock for the production of fuel-grade alcohol. In the current study, steam explosion of corn fiber at various degrees of severity was employed to evaluate the potential of using this feedstock in the bioconversion process. The parameters investigated were: temperature (150-230°C), residence time (1-9 min) and SO2 concentration (0-6% (w/w) dry matter). Subsequently, hydrolysis experiments were carried out at 2% (w/v) solid concentration of pretreated and washed corn fiber. Comparative fermentations of the hydrolyzates, post-treated hydrolyzates and the saccharified cellulose/starch residues were conducted with an industrially-adapted yeast. The effects of different parameters were described by surface-response modeling. The results indicated that maximum sugar yields
(soluble and following enzymatic hydrolysis) were recovered from corn fiber
that was pretreated at 190°C for 5 minutes with 3% SO2. Sequential SO2-catalyzed steam explosion and
enzymatic hydrolysis resulted in very high conversion (87%) of all
polysaccharides in the corn fiber to monomeric sugars. Subsequently, Saccharomyces cerevisiae
was able to convert the resultant corn fiber hydrolyzates, post-treated
hydrolyzates and the saccharified cellulose/starch residues to ethanol very
efficiently during the fermentation process.
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