Submitted to: Chemical Engineering Science
Publication Type: Abstract Only
Publication Acceptance Date: July 18, 1996
Publication Date: N/A
Technical Abstract: Most of the biofuel ethanol produced in the United States is derived from corn starch. The ethanol yield from corn could be significantly increased if the hemicellulose fraction of the corn kernel was also fermented. The hemicellulose and cellulose fractions are presently sold as low-value cattle feed. Conversion of hemicellulose to ethanol is problematic because hydrolysis of the hemicellulose gives a mixture of pentoses (L-arabinose and D-xylose) in addition to glucose. The yeast used to ferment hydrolyzed corn starch are unable to utilize pentoses. We have evaluated non-traditional recombinant microorganisms for conversion of the hemicellulose fractions into ethanol. The hemicelluloses were hydrolyzed by treating with weak acid solutions. The resulting sugar mixtures were fermented using recombinant Escherichia coli (strains K011 and SL40) and Klebsiella oxytoca (strain P2). Results of these fermentations will be discussed in terms of volumetric ethanol rates, ethanol yields, and the effects of inhibitors produced during hydrolysis.