Construction and regulation of microbial cell factories for enhancing the biosynthesis of O-acetyl-L-homoserine in Escherichia coli W3110 Biosynthesis of O-acetyl-L-homoserine in E. coli.

Abstract

O-Acetyl-L-homoserine (OAH) is a versatile platform compound with extensive potential applications. It is a key precursor for the synthesis of L-methionine and adenosylmethionine. Currently, the microbial fermentation process for the production of OAH still face challenges, such as low fermentation yield and long fermentation period. In this study, the supply of key precursors, including L-aspartic acid, L-homoserine and acetyl-CoA, were firstly enhanced, which increased the OAH production from 7.25 g/L to 12.95 g/L in shaking flask fermentation. Subsequently, the non-oxidative glycolysis pathway (NOG pathway) was constructed and optimized to minimize the carbon loss and improve the carbon sources utilization, resulting in an increase in OAH production to 15.59 g/L. Finally, by accelerating cell division and enhancing the glucose transport system, OAH production was further improved to 17.23 g/L. The OAH production of the engineered strain OAH23 achieved a production level of 66.25 g/L in a 5-L bioreactor for 68 h, with the yield of 0.41 g/g glucose. The metabolic regulation strategy outlined in this study offers valuable insights for the efficient biosynthesis of OAH and other acetylated amino acids in E. coli.