MpADC, an l-aspartate-[alpha]-decarboxylase, from Myzus persicae, that enables production of [beta]-alanine with high yield by whole-cell enzymatic catalysis

[beta]-Alanine is a precursor of many important pharmaceutical products and food additives, its market demand is continuously increasing nowadays. Whole-cell catalysis relying on the recombinant expression of key [beta]-alanine synthesizing enzymes is an important method to produce [beta]-alanine. Nevertheless, [beta]-alanine synthesizing enzymes found so far have problems including easy inactivation, low expression or poor catalytic activity, and it remains necessary to develop new enzymes. Herein, we characterized an l-aspartate-[alpha]-decarboxylase, MpADC, from an aphid, Myzus persicae. It showed excellent catalytic activity at pH 6.0-7.5 and 37 [degrees]C. With the help of chaperone co-expression and N-terminal engineering guided by AlphaFold2 structure prediction, the expression and catalytic ability of MpADC in Escherichia coli were significantly improved. Using 50 g/L of E. coli cells expressing the MpADC-[DELA]39 variant cultured in a 15-L fermenter, 232.36 g/L of [beta]-alanine was synthesized in 13.5 h, with the average [beta]-alanine yield of 17.22 g/L/h, which is best known so far. Our research should facilitate the production of [beta]-alanine in an environment-friendly manner.