文献类型：期刊文献

英文题名：Improving the Plasmid Stability by a Hok/Sok System for L-Homoserine Production in Escherichia Coli

作者：Sun, Bing-Yao[1]; Tao, Xin-Yi[1]; Sui, Hua-Lu[1]; Wang, Feng-Qing[1]; Liu, Qing-Hai[1]; Gao, Bei[1]; Zhao, Jian[2]; Ma, Yu-Shu[2]; Liu, Min[1]; Wei, Dong-Zhi[1]

机构：[1] Newworld Institute of Biotechnology, East China University of Science and Technology, China; [2] East China University of Science and Technology, China

年份：2021

外文期刊名：Research Square

收录：EI(收录号：20220149599)

语种：英文

外文关键词：Amino acids - Antibiotics - Bottles - DNA - Metabolic engineering - Metabolism - System stability

摘要：Background: The production of bioactive compounds using microbial hosts is considered a safe, cost competitive and scalable approach. However, the efficient engineering of cell factories with well stability, such as for the production of L-aspartate family amino acids and derivatives, remains an outstanding challenge. Results: In the work, the toxin/antitoxin system and genome modification strategy were used to construct a stable Escherichia coli strain for L-homoserine production. The metabolic engineering strategies were focused on the enhancement of precursors for L-homoserine synthesis, reinforcement of the NADPH generation and efflux transporters using CRISPR-Cas9 system at the genome level. To improve the plasmid stability, two strategies were explored, including construction of the aspartate-auxotrophic and hok/sok systems. Constructing the auxotrophic complementation system to maintain plasmid stability was failed herein. The plasmid stability was improved by introducing the hok/sok system, resulting in 6.1 g/L (shake flask) and 44.4 g/L (5 L fermenter) L-homoserine production of the final engineered strain SHL19 without antibiotics addition. Moreover, the hok/sok system was also used to improve the plasmid stability for ectoine production, resulting in 36.7% and 46.5% higher titer of ectoine at shake flask and 5L fermenter without antibiotics addition, respectively. Conclusion: This work provides valuable strategies to improve plasmid stability for producing L-aspartate family amino acids and derivatives and eliminate environmental concerns associated with the application of antibiotics. ? 2021, CC BY.