AnEscherichia colistrain containing a recombinant plasmid encoding the pyruvate decarboxylase and alcohol dehydrogenase genes fromZymomonas mobilismetabolized glucose and xylose to near theoretical yields of ethanol. Enzyme activity measurements indicate high expression levels of both plasmid-encodedZymomonasproteins in the recombinantE. coli. The expression inE. coliis under the control of a promoter in theZymomonassequence upstream of the pyruvate decarboxylase gene. The maximum ethanol level, using 4 glucose as substrate, was 1.8 (w/v) in anaerobic conditions. In aerobic conditions the natural repression ofE. colialcohol dehydrogenase results in less ethanol production from clones expressing onlyZymomonaspyruvate decarboxylase.
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