【摘要】 L-异亮氨酸是人体必需氨基酸之一,具有很大的商业价值。在谷氨酸棒杆菌中,合成一分子L-异亮氨酸需要消耗四分子NADPH。因此,提高胞内NADPH浓度是提高L-异亮氨酸产量的重要手段之一。在乳糖发酵短杆菌JHI3-156中过量表达酿酒酵母的NADH激酶编码基因POS5△MTS,发酵48 h表达菌株JHI3-156/pDXW-10-POS5△MTS的胞内NADP~+浓度增加了27μmol/L(17%),NADPH浓度增加了36μmol/L(96%);发酵72 h后L-异亮氨酸产量是(3.02±0.52)g/L,比对照菌(1.96±0.04)g/L提高了54%。本研究表明,过表达POS5△MTS基因能提高NADPH的供应,促进了L-异亮氨酸的生物合成。更多还原

【Abstract】 In Corynebacterium glutamicum,four molecules of NADPH are required for the generation of one molecule of L-isoleucine.Therefore to increase the intracellular NADPH concentration will contribute to L-isoleucine biosynthesis.In this paper,a NADH kinase gene of Saccharomyces cerevisiae POS5△MTS was overexpressed in a L-isoleucine producing strain C.glutamicum ssp.lactofermentum JHI3-156.The intracellular NADP~+ concentration and NADPH concentration in JHI3-156/pDXW10-POS5△MTS increased by 27 μmol/L(17%) and 36 μmol/L(96%),respectively.After 72 h,Lisoleucine production in the fermentation medium of JHI3-156/pDXW10- POS5△MTS increased to(3.02 ±0.52) g/L,about 54%higher than that by the control strain of(1.96 ± 0.04) g/L.These results suggested that overexpression of S.cerevisiae POS5△MTS gene could increase NADPH supply for the improvement of L-isoleucine biosynthesis.更多还原