Use of agricultural biomass, other than cornstarch, to produce fuel ethanol requires a microorganism that can ferment the mixture of sugars derived from hemicellulose. Escherichia coli metabolizes a wide range of substrates and has been engineered to produce ethanol in high yield from sugar mixtures. E. coli metabolizes glucose in preference to other sugars and, as a result, utilization of the pentoses in hemicellulose-derived sugar mixtures is delayed and may be incomplete. Residual sugar lowers the ethanol yield and is problematic for downstream processing of fermentation products. Therefore, a catabolite repression mutant that simultaneously utilizes glucose and pentoses would be useful for fermentation of complex substrate mixtures. We constructed ethanologenic E. coli strains with a glucose phosphotransferase (ptsG) mutation and used the mutants to ferment glucose, arabinose, and xylose, singly and in mixtures, to ethanol. Yields were 87–94% of theoretical for both the wild type and mutants, but the mutants had an altered pattern of mixed sugar utilization. Phosphotransferase mutants metabolized the pentoses simultaneously with glucose, rather than sequentially. Based upon fermentations of sugar mixtures, a catabolite-repression mutant of ethanologenic E. coli is expected to provide more efficient fermentation of hemicellulose hydrolysates by allowing direct utilization of pentoses.
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Similar content being viewed by others Explore related subjectsDiscover the latest articles and news from researchers in related subjects, suggested using machine learning. Author information Authors and AffiliationsFermentation Biochemistry Research Unit, National Center for Agricultural Utilization Research, USDA, Agricultural Research Service, 1815 N. University Street, Peoria, IL 61604, USA, , , , ,
N. Nichols, B. Dien & R. Bothast
Received revision: 12 December 2000
Electronic Publication
About this article Cite this articleNichols, .N., Dien, .B. & Bothast, .R. Use of catabolite repression mutants for fermentation of sugar mixtures to ethanol. Appl Microbiol Biotechnol 56, 120–125 (2001). https://doi.org/10.1007/s002530100628
Received: 22 September 2000
Accepted: 29 December 2000
Issue Date: July 2001
DOI: https://doi.org/10.1007/s002530100628
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