基于基因转录和代谢物分析的异亮氨酸生产菌谷氨酸棒状杆菌YILW的理性改造（英文）

发布时间：2018-06-12 21:37

本文选题：谷氨酸棒杆菌 + 异亮氨酸　；参考：《食品科学》2017年04期

【摘要】：为获得异亮氨酸生产菌谷氨酸棒状杆菌(Corynebacterium glutamicum)YILW的理性改造策略,考察该菌株与出发菌株C.glutamicum ATCC 13032异亮氨酸合成途径中关键酶及代谢产物的差异。结果表明,C.glutamicum YILW丙酮酸羧化酶编码基因pyc的下调表达使得其胞内草酰乙酸含量降低,过表达该基因显著增加胞内草酰乙酸含量及异亮氨酸产量(分别从1.32μmol/g(细胞干质量,下同)和5.18 g/L提高至3.32μmol/g和5.81 g/L),但副产物赖氨酸及胞内2-酮丁酸积累量提高。针对该问题采用强启动子替换手段过表达ilv BNC操纵子,使得其异亮氨酸产量提高至6.63 g/L。为进一步增加异亮氨酸合成,过表达输出载体编码基因brn E和brn F,其产量提高至7.31 g/L,较出发菌株C.glutamicum YILW提高41.1%,转化率提高40.0%。由此可见,在基因转录及代谢物分析结果指导下理性过表达pyc、ilv BNC操纵子及brn E和brn F能够显著提高异亮氨酸产量并降低副产物浓度。
[Abstract]:In order to obtain the rational transformation strategy of the isoleucine producing strain of Corynebacterium glutamicum YILW, the difference between the key enzymes and the metabolites of the isoleucine synthesis pathway of the strain and the starting strain C.glutamicum ATCC 13032 was investigated. The results showed that the down regulated expression of the C.glutamicum YILW pyruvate carboxylase encoding gene PyC was expressed. The content of cytosolic acetoacetic acid was reduced, and overexpression of the gene significantly increased the content of cytosolic acyacoacetic acid and the production of isoleucine (1.32 mol/g (cell dry mass, the same below) and 5.18 g/L to 3.32 mu mol/g and 5.81 g/L respectively, but the accumulation of the byproduct lysine and intracellular 2- ketobutyric acid increased. Changing the expression of ILV BNC operon, the production of isoleucine increased to 6.63 g/L. to further increase isoleucine synthesis, overexpression of the output vector encoding gene BRN E and BRN F, and its yield increased to 7.31 g/L, which was 41.1% higher than that of the starting strain C.glutamicum YILW, and the conversion rate increased 40.0%. here, in gene transcription and metabolites. Under the guidance of the results, rational overexpression of PyC, ILV BNC operon and BRN E and BRN F can significantly increase isoleucine production and reduce the concentration of by-products.
【作者单位】：天津科技大学生物工程学院代谢控制发酵技术国家地方联合工程实验室;
【基金】：国家高技术研究发展计划(863计划)项目(2013AA102106) 国家自然科学基金青年科学基金项目(31300069) 天津市科技特派员项目(15JCTPJC62800)
【分类号】：TS201.3

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