Zhu Xinggui, Wu Mingke, Ma Jiangfeng, Gao Youjun, Chen Meili, Jiang Min
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu, China.
Changmao Biochemical Engineering Company Limited, Changzhou 213034, Jiangsu, China.
Sheng Wu Gong Cheng Xue Bao. 2016 Oct 25;32(10):1372-1380. doi: 10.13345/j.cjb.160114.
Hyper-osmotic stress is one of the key factors that decrease the efficiency of biological succinic acid production. To increase the osmotic stress tolerance of succinate-producing Escherichia coli, we studied the influence of IrrE, an exogenous global regulator, on cell osmotic stress resistance. Fermentation results showed that cell growth and succinic acid production by the recombinant increased under different Na+ concentrations. Meanwhile, the maximum dry cell mass, glucose consumption and succinic acid concentration increased 15.6%, 22% and 23%, respectively, when fermented in a 5-L bioreactor. Expressing IrrE improved cell resistance to hyper-osmotic stress. Further comparison of intracellular osmoprotectants (trehalose and glycerol) concentrations showed that trehalose and glycerol concentrations in the recombinant increased. This suggested that introduction of IrrE could enhance intracellular osmoprotectants accumulation which conferred cell with improved resistance to osmotic stress.
高渗胁迫是降低生物琥珀酸生产效率的关键因素之一。为提高产琥珀酸大肠杆菌对渗透胁迫的耐受性，我们研究了外源全局调节因子IrrE对细胞抗渗透胁迫能力的影响。发酵结果表明，重组菌在不同Na+浓度下细胞生长和琥珀酸产量均有所增加。同时，在5-L生物反应器中发酵时，最大干细胞质量、葡萄糖消耗量和琥珀酸浓度分别提高了15.6%、22%和23%。表达IrrE提高了细胞对高渗胁迫的抗性。进一步比较细胞内渗透保护剂（海藻糖和甘油）浓度发现，重组菌中海藻糖和甘油浓度增加。这表明引入IrrE可增强细胞内渗透保护剂的积累，从而赋予细胞更好的抗渗透胁迫能力。
