四氢嘧啶
谷氨酸棒杆菌
盐单胞菌属
代谢工程
大肠杆菌
生物化学
质粒
生产过剩
发酵
生物
酶
细菌
脱氢酶
化学
微生物学
渗透调节剂
基因
遗传学
氨基酸
16S核糖体RNA
脯氨酸
作者
Lihong Li,Ning Li,Xinglong Wang,Song Gao,Juan Zhang,Jingwen Zhou,Zhimeng Wu,Weizhu Zeng
标识
DOI:10.1016/j.biortech.2023.129862
摘要
Ectoine, a natural protective agent, is naturally synthesized at low titers by some extreme environment microorganisms that are usually difficult to culture. There is a need for an efficient and eco-friendly ectoine production process. In this study, Escherichia coli BL21(DE3) with the ectABC gene cluster from Halomonas venusta achieved 1.7 g/L ectoine. After optimizing the expression plasmid, 2.1 g/L ectoine was achieved. Besides, the aspartate kinase mutant LysCT311I from Corynebacterium glutamicum and aspartate semialdehyde dehydrogenase from Halomonas elongata were overexpressed to increase precursors supply. Furthermore, the rate-limiting enzyme EctB was semirationally engineered, and the E407D mutation enhanced ectoine production by 13.8 %. To improve acetyl-CoA supply, the non-oxidative glycolysis pathway was introduced. Overall, the optimized strain ECT9-5 produced 67.1 g/L ectoine by fed-batch fermentation with a 0.3 g/g of glucose and the kinetic model resulted in a good fit.
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