中文摘要：

钝齿棒杆菌（Corynebacterium crenatum）SYPA5-5是诱变选育的一株高产精氨酸菌株.柠檬酸合酶作为TCA途径的关键酶,对细胞胞内氨基酸代谢流调节有重要作用.在钝齿棒杆菌SYPA5-5中过量表达同源的柠檬酸合酶（citrate synthase）基因 prpC2 ,研究其对精氨酸及副产物合成的影响.重组菌C. crenatum SYPA5-5/pDXW-10-prpC2 胞内柠檬酸合酶比酶活提高了5.37倍,使L-精氨酸产量在5L发酵罐中达到44.7g/L,与对照相比提高了23.1%.同时,有机酸测定分析TCA循环的精氨酸前体柠檬酸及异柠檬酸的量有所提高,且赖氨酸合成前体草酰乙酸量减少,氨基酸测定分析L-精氨酸发酵中最主要的副产物L-赖氨酸浓度由原来的5.96g/L降到1.21g/L,降低了80%.

英文摘要：

Corynebacterium crenatum SYPA5-5 is an L-arginine high-producing industrial strain of mutation breeding. The role of citrate synthase in L-arginine biosynthesis was investigated by overexpressing the citrate synthase （prpC2） gene in C. crenatum SYPA5-5. The resultant 5.37-fold increase in intracellular citrate synthase activity was achieved in the prpC2-overexpressing strain C. crenatum SYPA5-5/pDXW-10-prpC2 . The recombinant strain enhanced the L-arginine yield to 44.7g/L by about 23.1% in 5L fermenter, as compared to the control, with affecting glucose depletion rate slightly. While the L-arginine yield increased in the prpC2-overexpressing strain, the L-lysine yield, the most primary by-product formation during L-arginine fermentation, decreased to 1.21g/L from the original concentration 5.96g/L, correlating with an increase in the tricarboxylic acid cycle （TCA） intermediates （citrate and isocitrate） and an increase in the activity of citrate synthase.