Metabolic engineering and pathway construction for -acetyl-L-homoserine production in .

UNLABELLED

-Acetyl-L-homoserine (OAH) is a potentially important platform metabolic intermediate for the production of homoserine lactone, methionine, 1,4-butanediol and 1,3-propanediol which have giant market value. Currently, multiple strategies have been adopted to explore sustainable production of OAH. However, the production of OAH by consuming cheap bio-based feedstocks with as the chassis is still in its infancy. Construction of high yield OAH-producing strains is of great significance in industry. In this study, we introduced an exogenous from () and engineered an OAH-producing strain by combinatorial metabolic engineering. Initially, exogenous were screened and used to reconstruct an initial biosynthesis pathway of OAH in . Subsequently, the disruption of degradation and competitive pathways combined with optimal expression of were carried out, accumulating 5.47 g/L OAH. Meanwhile, the homoserine pool was enriched by overexpressing with producing 7.42 g/L OAH. Lastly, the carbon flux of central carbon metabolism was redistributed to balance the metabolic flux of homoserine and acetyl coenzyme A (acetyl-CoA) in OAH biosynthesis with accumulating 8.29 g/L OAH. The engineered strain produced 24.33 g/L OAH with a yield of 0.23 g/g glucose in fed-batch fermentation. By these strategies, the key nodes for OAH synthesis were clarified and corresponding strategies were proposed. This study would lay a foundation for OAH bioproduction.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-023-03564-5.