[氧剥夺条件下嗜酸棒杆菌-deltaldh的代谢转变]
[Metabolic shift of Corynebacterium acetoacidophilum-deltaldh under oxygen deprivation conditions].
作者信息
Yang Qian, Zheng Pu, Yu Fang, Liu Wei, Sun Zhihao
出版信息
Sheng Wu Gong Cheng Xue Bao. 2014 Mar;30(3):435-44.
Lactate and succinate were produced by Corynebacterium acetoacidophilum from glucose under oxygen deprivation conditions. To construct knockout mutant, lactate dehydrogenase gene (ldh) of C. acetoacidophilum was deleted by double-crossover chromosome replacement with sacB gene. Comparing with the wild strain ATCC13870, ldhA-deficent mutant produced no lactate with glucose consumption rate decreased by 29.3%, while succinate and acetate concentrations were increased by 45.6% and 182%, respectively. Moreover, the NADH/NAD+ rate was less than 1 (about 0.7), and the activities of phosphoenolpyruvate carboxylase and acetate kinase of the ldhA-deficent mutant were enhanced by 84% and 12 times, respectively. Our studies show that succinicate and acetate production pathways are strengthened by blocking lactate synthesis. It also suggests that improving NADH supply and eliminating acetate generation are alternative strategies to get high succinate-producer.
在缺氧条件下,嗜酸醋酸棒杆菌可利用葡萄糖产生乳酸和琥珀酸。为构建基因敲除突变体,采用携带sacB基因的双交换染色体替换法,删除了嗜酸醋酸棒杆菌的乳酸脱氢酶基因(ldh)。与野生菌株ATCC13870相比,ldhA缺陷型突变体不产生乳酸,葡萄糖消耗率降低了29.3%,而琥珀酸和乙酸的浓度分别增加了45.6%和182%。此外,NADH/NAD+比率小于1(约为0.7),ldhA缺陷型突变体的磷酸烯醇式丙酮酸羧化酶和乙酸激酶的活性分别提高了84%和12倍。我们的研究表明,通过阻断乳酸合成可增强琥珀酸和乙酸的产生途径。这也表明,改善NADH供应和消除乙酸生成是获得高产琥珀酸菌株的替代策略。