Mutant ilvH gene and method for producing L-valine

摘要

The present invention provides an isolated DNA molecule encoding a small subunit of acetohydroxy acid synthase isozyme III originating from Escherichia coli and mutants of Escherichia coli acetohydroxy acid synthase isozyme III, which are free from inhibition by L-valine an can catalyze the conversion of: (a) pyruvate to alpha-acetolactate and (b) alpha-ketobutyrate and pyruvate to alpha-aceto-a-hydroxybutyrate. The present invention also provides methods for producing L-valine by fermentation of a bacterium harboring the novel DNA molecule and/or expressing the mutant acetohydroxy acid synthase isozyme III.