proC及putP基因的敲除对钝齿棒杆菌产L-精氨酸生理代谢的影响

Effects of pro C and put P Deletion on Physiological Metabolism of L-arginine-producing Strain Corynebacterium crenatum

为了选育精氨酸高产菌株,基于谷氨酸棒杆菌的基因组尺度代谢网络模型的指导,以钝齿棒杆菌(Corynebacterium crenatum)MT-M4为出发菌株,通过基因敲除技术构建了pro C和put P敲除菌株。摇瓶发酵结果表明,pro C敲除菌株精氨酸产量达到9.94g/L,较出发菌株提高了15.90%,葡萄糖转化率提高了26.02%。由于其生长受到明显抑制,因此在发酵液中外源添加24mmol/L的脯氨酸,结果发现其精氨酸产量达到12.22g/L,且菌株恢复生长。put P敲除菌株精氨酸产量达到12.23g/L,较出发菌株提高了42.70%,葡萄糖转化率提高了49.31%。以上结果显示,put P的敲除比pro C的敲除更有利于精氨酸的合成,put P的敲除对菌株的生理代谢基本无影响且无需外添加脯氨酸。

The recombinant strains of C. crenatum MT-M4 Δpro C and C. crenatum MT-M4 Δput P were separately constructed based on genome-scale metabolic network model（ GSMN） of Corynebacterium glutamicum.As results shown, L-arginine production of C. crenatum MT-M4 Δpro C was significantly increased by approximately 15. 90% higher than that of the original strain,reached to 9. 94 g / L with glucose transformation rate increased by 26. 02%. However,the growth of C. crenatum MT-M4 Δpro C was obviously inhibited. When24 mmol / L of proline was added,the arginine production reached to 12. 22 g / L and its growth also got well. The L-arginine production of C. crenatum MT-M4 Δput P was significantly increased by 42. 70% and reached to12. 23 g / L with glucose transformation rate increased by 49. 31%. The results showed that put P deletion compared with pro C deletion was more conducive to L-arginine biosynthesis. The disruption of put P had no influence on the physiological metabolism of the bacteria strain and the mutant strain did not need proline added in medium.