细胞分裂蛋白编码基因的敲除对丙酮丁醇梭菌溶剂合成与细胞形态的影响

Effects of cell division protein-encoding genes knockout on solvent formation and cell morphology in Clostridium acetobutylicum

摘要:

丙酮丁醇梭菌是生物丁醇合成的重要菌株，近年来，研究者们利用基因编辑等技术对其进行菌株改造。通过对丙酮丁醇梭菌中3个细胞分裂蛋白 (RodA、DivIVA、DivIB) 编码基因 (cac1251、cac2118、cac2125) 进行敲除，发现cac2118敲除菌株的细胞在产溶剂期为球状形态，细胞变小，ABE发酵的丁醇得率为0.19 g/g，与野生型相比提高了5.6%。cac1251敲除菌株的葡萄糖消耗量和丁醇产量与野生型相比降低了33.9%和56.3%，分别为47.3 g/L和5.6 g/L。cac1251和cac2125的敲除对细胞生长有显著影响，菌体浓度最大值与野生型相比分别降低了40.4%和38.3%。研究表明细胞分裂蛋白DivIVA对细胞的形态和大小调控起重要作用；细胞分裂蛋白RodA和DivIB调控细胞分裂进程，进而影响细胞生长和溶剂合成进程。

Abstract:

Clostridium acetobutylicum is an important strain for bio-butanol formation. In recent years, gene-editing technology is widely used for developing the hyper-butanol-production strains. In this study, three genes (cac1251, cac2118 and cac2125) encoding cell division proteins (RodA, DivIVA and DivIB) in C. acetobutylicum were knocked out. The cac2118-knockout strain had changed its cell morphology to spherical-shape during the solventogenesis, and obtained a higher butanol yield of 0.19 g/g, increasing by 5.5%, compared with the wild type strain. The glucose utilization and butanol production of cac1251-knockout strain decreased by 33.9% and 56.3%, compared the with wild type strain, reaching to 47.3 g/L and 5.6 g/L. The cac1251-knockout strain and cac2125-knockout strain exhibited poor cell growth with cell optical density decreased by 40.4% and 38.3%, respectively, compared with that of the wild type strain. The results indicate that cell division protein DivIVA made the differences in the regulation of cell morphology and size. Cell division proteins RodA and DivIB played significant roles in the regulation of cell division, and affected cell growth, as well as solventogenesis metabolism.