中文摘要：

旁支代谢途径的截断有利于目的氨基酸合成途径的集流。基于基因组尺度代谢网络模型的预测,以钝齿棒杆菌（Corynebacterium crenatum）MT-M4为出发菌株,通过无痕敲除技术分别敲除了编码磷酸乙酰基转移酶的pta基因及编码乙酸激酶的ack基因,阻断了乙酸的合成。摇瓶发酵结果表明,pta缺失菌株精氨酸产量较出发菌株提高了25.60%,达15.46g/L。葡萄糖转化率提高了29.41%;ack缺失菌株精氨酸产量达13.82g/L,较出发菌株提高了12.81%,葡萄糖转化率提高了26.02%。同时,pta及ack敲除菌株的细胞生长较出发菌株均分别提高了9.19%及7.71%。因此,pta、ack的敲除不仅有利于精氨酸的合成,而且对菌体生长具有促进作用;但pta的敲除更有利于精氨酸的积累。

英文摘要：

The disruption of competitive metabolic pathways is conducive to the carbon flux converted into the purpose amino acid biosynthetic pathway. In the present study,based on the prediction of genome-scale metabolic network model,markless knock-out technology to construct separately recombinant strains C. crenatum MT-M4 △pta and C. crenatum MT-M4 △ack which led to interdict the acetic acid biosynthetic pathway were employed. As shake-flask fermentation results shown,L-arginine production of C. crenatum MT-M4 △pta was significantly increased by 25. 60% higher than that of original strain,reached to 15. 46 g / L with glucose transformation rate increased by 29. 41%. L-arginine production of C. crenatum MT-M4 △ack was 13. 82 g / L which was 12. 81% higher than that of original strain,with glucose transformation rate increased by 26. 02%. In addition,the growth of C. crenatum MT-M4 △pta and C. crenatum MT-M4 △ack was increased by 9. 19% and7. 71%,respectively. Thus,pta and ack deletion was not only beneficial to the improvement of L-arginine production,but also conducive to the cell growth. However,pta deletion compared with ack deletion was more conducive to L-arginine accumulation.