Influence of L-isoleucine and pantothenate auxotrophy for L-valine formation in Corynebacterium glutamicum revisited by metabolome analyses.

The effect of different amounts of supplemented L-isoleucine and pantothenate has been analysed with the auxotrophic strain Corynebacterium glutamicum DeltailvA DeltapanB, showing that the final biomass concentration of this preliminary L-valine production strain can be controlled by the amount of added L-isoleucine. One gramme cell dry weight is formed from 48 micromol L-isoleucine. Different amounts of available pantothenate affect the intracellular pyruvate concentration. By limiting pantothenate supplementation from 0.8 to 0.1 microM, a 35-fold increase of cytoplasmic pyruvate up to 14.2 mM can be observed, resulting in the increased formation of L-valine, L-alanine and organic acids in the presence of low pantothenate concentrations. These findings can be used to redirect the carbon flux from glycolysis via pyruvate to the TCA cycle towards the desired product L-valine.