Metabolic engineering of <i>Escherichia coli</i> for the biosynthesis of O-acetyl-L-homoserine.

Lianggang HUANG; Feng GAO; Nuoran XU; Junping ZHOU; Kun NIU; Bo ZHANG; Zhiqiang LIU; Yuguo ZHENG

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Metabolic engineering of Escherichia coli for the biosynthesis of O-acetyl-L-homoserine.

Author: Lianggang HUANG ¹ ; Feng GAO ¹ ; Nuoran XU ¹ ; Junping ZHOU ¹ ; Kun NIU ¹ ; Bo ZHANG ¹ ; Zhiqiang LIU ¹ ; Yuguo ZHENG ¹
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1. College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
Publication Type:Journal Article
Keywords: Escherichia coli; O-acetyl-L-homoserine; acetic acid reuse; co-factor engineering; metabolic engineering
MeSH: Metabolic Engineering/methods*; Escherichia coli/genetics*; Homoserine/biosynthesis*; Fermentation
From: Chinese Journal of Biotechnology 2025;41(1):256-270
CountryChina
Language:Chinese
Abstract: O-acetyl-L-homoserine (OAH) is a promising platform compound for the production of L-methionine and other valuable compounds, while its low yield and low conversion rate limit the industrial application. To solve these problems, we constructed a strain for high OAH production with the previously constructed L-homoserine producer Escherichia coli HS33 as the chassis by systematic metabolic engineering. Firstly, PEP accumulation, pyruvate utilization, and OAH synthesis pathway (overexpressing aspB, aspA, and thrA^C1034T) were enhanced to obtain an initial strain accumulating 13.37 g/L OAH. Subsequently, the co-factor synthesis genes were integrated to supply reducing power and energy, which increased the yield to 15.79 g/L. The OAH yield of the engineered strain OAH28 was further increased to 17.49 g/L by strengthening the acetic acid reuse pathway, improving the supply of acetyl-CoA, and regulating the expression of MetX from different sources. Finally, in a 5 L fermenter, OAH28 achieved an OAH titer of 47.12 g/L, with a glucose conversion rate of 32% and productivity of 0.59 g/(L·h). The results lay a foundation for increasing the OAH production by metabolic engineering and give insights into the industrial production of OAH.