Abstract L-Homoserine is a platform chemical used for the production of l -methionine and other valuable compounds. In this study, we constructed an initial l -homoserine-producing strain by metabolic engineering of Corynebacterium glutamicum ATCC 13032, including deletion of thrB, mcbR, and metD and overexpression of lysC, asd, and hom, resulting in a strain capable of producing 1.2 g/L l -homoserine and 4.8 g/L l -lysine. The metabolic flux of l -homoserine was further enhanced by overexpressing feedback-insensitive pyruvate carboxylase (encoded by pyc) from C. glutamicum ATCC 13032 and l -aspartate aminotransferase (encoded by aspC) from E. coli in order to increase oxaloacetate and l -aspartate supplies. Additionally, overexpression of brnFE, which encodes the two-component export system, improved l -homoserine production by 2-fold, suggesting involvement of the brnFE operon in l -homoserine export. Moreover, attenuated expression of dapA and icd downregulated l -lysine biosynthesis and the TCA cycle, resulting in a 25.9 % increase in l -homoserine production (up to 3.4 g/L). Furthermore, overexpression of lysCT311I, asd from C. glutamicum ATCC 13032, and the thrAS345F from E. coli K12-MG1655 resulted in l -homoserine production of 8.8 g/L and demonstrated C. glutamicum as having great potential for industrial production of l- homoserine and l -methionine.

中文翻译：

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通过代谢通量的再分配在谷氨酸棒杆菌 ATCC 13032 中高效生产 L-高丝氨酸

摘要 L-高丝氨酸是一种平台化学品，用于生产L-蛋氨酸和其他有价值的化合物。在本研究中，我们通过谷氨酸棒杆菌 ATCC 13032 的代谢工程构建了一个初始产 l-高丝氨酸菌株，包括 thrB、mcbR 和 metD 的缺失以及 lysC、asd 和 hom 的过表达，从而产生了能够产生 1.2 的菌株g/L l-高丝氨酸和 4.8 g/L l-赖氨酸。通过过度表达来自谷氨酸棒杆菌 ATCC 13032 的反馈不敏感丙酮酸羧化酶（由 pyc 编码）和来自大肠杆菌的 l-天冬氨酸转氨酶（由 aspC 编码），以增加草酰乙酸和 l-天冬氨酸供应。此外，编码双组分输出系统的 brnFE 的过表达将 l-高丝氨酸产量提高了 2 倍，表明 brnFE 操纵子参与 l-高丝氨酸输出。此外，dapA 和 icd 的表达减弱会下调 l-赖氨酸生物合成和 TCA 循环，导致 l-高丝氨酸产量增加 25.9%（高达 3.4 g/L）。此外，lysCT311I、来自谷氨酸棒杆菌 ATCC 13032 的 asd 和来自大肠杆菌 K12-MG1655 的 thrAS345F 的过表达导致 8.8 g/L 的 l-高丝氨酸产量，并证明谷氨酸棒杆菌具有巨大的 l-高丝氨酸生产潜力。高丝氨酸和 l-蛋氨酸。