Submitted to: Corn Dry Milling Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 31, 1996
Publication Date: N/A
Technical Abstract: Currently, corn fiber co-products such as corn hulls (fiber) and de-oiled germ (germ cake/meal) are sold as animal feeds. We are examining other possible uses of these co-products. Most of the fuel ethanol produced in the United States is derived from the yeast fermentation of corn starch. The ethanol yield from corn could be significantly increased (up to 0.3 gal/bushel) if the residual starch and hemicellulose fractions of these co-products could be fermented. Conversion of hemicellulose to ethanol is problematic because hydrolysis of it yields pentose sugars (arabinose and xylose) which cannot be fermented by the traditional yeast used to ferment hydrolyzed starch. However, bacteria have been genetically engineered to produce ethanol. We have evaluated the genetically engineered Escherichia coli strains KO11 and SL40. Corn fiber and corn germ meal were hydrolyzed with dilute acid to produce sugar mixtures. Both strains KO11 and SL40 were found to effectively produce ethanol from these sugar mixtures. As an alternative to ethanol production, intact corn hemicelluloses themselves represent potential high value products. We have developed novel procedures using non-toxic chemicals to extract hemicelluloses from corn fiber and corn germ. The isolated hemicelluloses are highly pure, water soluble, and produce clear, viscous solutions. Potential uses of the hemicelluloses include thickening agents and replacements for other commercial gums.