代谢工程改造谷氨酸棒杆菌合成四氢嘧啶

Metabolic engineering of Corynebacterium glutamicum for ectoine production

为了获得四氢嘧啶生产菌株并利用此菌株提高四氢嘧啶产量,以谷氨酸棒杆菌(Corynebacterium glutamicum)野生菌株ATCC13032为研究对象,以赖氨酸积累量为评价指标,强化了天冬氨酸-β-半醛合成代谢流;通过阻断赖氨酸输出通道LysE,表达不同来源的四氢嘧啶操纵子ectABC,获得了四氢嘧啶生产菌株;通过强化天冬氨酸转氨酶和还原型烟酰胺腺嘌呤二核苷酸磷酸(NADPH)再生途径,进一步提高四氢嘧啶产量。结果表明,构建了一株高产赖氨酸的谷氨酸棒杆菌工程菌株LYS-3,赖氨酸积累量为28.48 g/L;表达操纵子HEectABC的谷氨酸棒杆菌ECT-3四氢嘧啶产量达到17.21 g/L;过表达基因aspC和ECpntAB谷氨酸棒杆菌ECT-6,摇瓶发酵四氢嘧啶产量达到21.85 g/L。研究结果可为天冬氨酸-β-半醛衍生物的生物合成提供参考。

Aiming to obtain the ectoine-producing strain and use it to increase the yield of ectoine,using wild strain Corynebacterium glutamicum ATCC13032 as research object,lysine accumulation amount as evaluation index,the aspartic acid-β-semialdehyde synthesis metabolism flow was strengthened.The ectoine operon ectABC from different sources was expressed by blocking the lysine export channel LysE,and the ectoine-producing strains were obtained.The ectoine production further increased by strengthening the regeneration pathway of aspartate aminotransferase and nicotinamide adenine dinucleotide phosphate(NADPH).The results showed that a high-yield lysine C.glutamicum engineering strain LYS-3 was constructed,and the lysine accumulation amount was 28.48 g/L.The ectoine production of C.glutamicum ECT-3 expressing operon HEectABC reached 17.21 g/L.The ectoine production C.glutamicum ECT-6 overexpressing gene aspC and ECpntAB reached 21.85 g/L in shake flask.The research results could provide a reference for the biosynthesis of aspartic acid-β-semialdehyde derivatives.