Production of l-alanyl-l-glutamine by recycling E. coli expressing α-amino acid ester acyltransferase.

In this study, the optimum induction and reaction conditions, and fermentation process of producing Ala-Gln by E. coli Origami 2 overexpressing α-amino acid ester acyltransferase (OPA) were investigated. Besides, the Ala-Gln synthesis by OPA achieved the maximum molar yield of 94.7% and productivity of 1.89g/L/min due to the extremely high enzyme activity. On this basis, repeated-cycle batch fermentation to produce Ala-Gln indicated that OPA could maintain high Ala-Gln yields and enzyme stabilities after several cell recycling. Consequently, the cost-efficient and environmentally friendly approach for Ala-Gln production by recycling OPA makes a great contribution to further industrial-scale applications.