代谢工程改造大肠杆菌生产l-高丝氨酸

Metabolic engineering of Escherichia coli for l-homoserine production

摘要:

l-高丝氨酸是一种非必需氨基酸，在工业生产中常被用作重要的平台化合物和添加剂。为提高产物合成效率，本文以实验室构建的l-高丝氨酸高产工程菌大肠杆菌Escherichia coli H0-0作为底盘菌株进行代谢改造。首先对ppc和pyccgP458S基因进行过表达来优化柠檬酸循环，然后通过thrAC1034T和lysCcgC932T提高产物的合成效率，随后对iclR基因进行了敲除以减少副产物的积累。同时导入scrA、scrB、scrK三个蔗糖代谢基因使大肠杆菌能利用蔗糖作为碳源进行发酵。l-高丝氨酸产量从3.2 g/L提高至11.1 g/L，本研究也为l-高丝氨酸的工业化生产奠定了基础。

Abstract:

l-Homoserine is a non-essential amino acid that is often used as an important platform compound and additive in industrial production. To improve the production efficiency, a previously constructed l-homoserine producing strain E. coli H0-0 was used as a chassis for further metabolic modification. Firstly, the ppc and pyccgP458S genes were overexpressed to optimize the Kreb’s cycle. Subsequently, thrAC1034T and lysCcgC932T were overexpressed to improve the product synthesis, followed by inactivation of iclR gene to reduce the accumulation of by-products. The introduction of three sucrose metabolism genes, scrA, scrB and scrK, enabled E. coli to ferment sucrose. The titer of l-homoserine increased from 3.2 g/L to 11.1 g/L.