Production of phenylpyruvic acid by engineered l-amino acid deaminase from Proteus mirabilis

This study aimed to develop an efficient enzymatic strategy for the industrial production of phenylpyruvate (PPA) from L-phenylpyruvic acid (L-Phe).L-amino acid deaminase from Proteus mirabilis was expressed in Escherichia coli BL21 (DE3) and modified to release product inhibition by employing conformational dynamics engineering. Based on structural analysis, two residues (E145/L341) were identified for reducing interactions between the product and enzyme and increasing flexibility of the protein, thereby facilitating the product release. The mutant M2E145A/E341A exhibited a 3.84-fold reduction in product inhibition and a 1.35-fold increase in catalytic efficiency in comparison to the wild type. Finally, 81.2 g/L PPA production with a conversion of 99.6% was obtained in a 5-L bioreactor.The engineered catalyst can significantly reduce product inhibition and facilitate the effective industrial synthesis of PPA.