variants coding pyruvate dehydrogenase improve the generation of pyruvate-derived acetoin.

Several chromosomally expressed AceE variants were constructed in and compared using glucose as the sole carbon source. These variants were examined in shake flask cultures for growth rate, pyruvate accumulation, and acetoin production via heterologous expression of the and genes from . The best acetoin-producing strains were subsequently studied in controlled batch culture at the one-liter scale.

Pyruvate Production by Escherichia coli by Use of Pyruvate Dehydrogenase Variants.

Altering metabolic flux at a key branch point in metabolism has commonly been accomplished through gene knockouts or by modulating gene expression. An alternative approach to direct metabolic flux preferentially toward a product is decreasing the activity of a key enzyme through protein engineering. In Escherichia coli, pyruvate can accumulate from glucose when carbon flux through the pyruvate dehydrogenase complex is suppressed.