Enhanced production of L-phenylalanine in Corynebacterium glutamicum due to the introduction of Escherichia coli wild-type gene aroH.

Metabolic engineering is a powerful tool which has been widely used for producing valuable products. For improving L-phenylalanine (L-Phe) accumulation in Corynebacterium glutamicum, we have investigated the target genes involved in the biosynthetic pathways. The genes involved in the biosynthesis of L-Phe were found to be strictly regulated genes by feedback inhibition. As a result, overexpression of the native wild-type genes aroF, aroG or pheA resulted in a slight increase of L-Phe. In contrast, overexpression of aroF (wt) or pheA (fbr) from E. coli significantly increased L-Phe production. Co-overexpression of aroF (wt) and pheA (fbr) improved the titer of L-Phe to 4.46 ± 0.06 g l⁻¹. To further analyze the target enzymes in the aromatic amino acid synthesis pathway between C. glutamicum and E. coli, the wild-type gene aroH from E. coli was overexpressed and evaluated in C. glutamicum. As predicted, upregulation of the wild-type gene aroH resulted in a remarkable increase of L-Phe production. Co-overexpression of the mutated pheA (fbr) and the wild-type gene aroH resulted in the production of L-Phe up to 4.64 ± 0.09 g l⁻¹. Based on these results we conclude that the wild-type gene aroH from E. coli is an appropriate target gene for pathway engineering in C. glutamicum for the production of aromatic amino acids.