Monday, August 11, 2008 - 2:00 PM
S40
Conversion of Sugar Mixtures in the Presence of Acetic Acid
Mark A. Eiteman and Elliot Altman. Cmbe, University of Georgia, Driftmier, Athens, GA 30602
We report a new approach for the simultaneous conversion of sugar mixtures in the presence of acetic acid into products by microbial processes. The process uses substrate-selective strains simultaneously in one bioreactor. Such strains are each able to consume only one substrate. For example, a strain which is unable to consume glucose and a strain unable to consume xylose will both together consume a xylose-glucose mixture at the maximal rate. We examined this concept using strains of Escherichia coli and mixtures of xylose, glucose and acetic acid. The xylose-selective (glucose deficient) strain has mutations in the glk, ptsG and manZ genes while the glucose-selective (xylose deficient) strain has a mutation in the xylA gene. An acetate-selective strain has all four mutations, and therefore will leave xylose and glucose unconsumed. We demonstrate that the process is able to adapt to changing concentrations of these two sugars, and therefore holds promise for the conversion of variable sugar feed streams, such as lignocellulosic hydrolysates. Two examples of this approach are the formation of lactic acid and the formation of ethanol.
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See more of Invited Oral Papers
See more of The Annual Meeting and Exhibition 2008 (August 10 - 14, 2008)