Wei Dong, Yuminaga Yuki, Shi Jiping, Hao Jian
Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Pudong, Shanghai, 201210, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, China.
Biotechnol Lett. 2018 Apr;40(4):679-687. doi: 10.1007/s10529-018-2524-5. Epub 2018 Feb 10.
To investigate the outcomes of capsule lost on cell transformation efficiency and chemicals (1,3-propanediol, 2,3-butanediol, and 2-ketogluconic acid) production by Klebsiella pneumoniae.
The cps gene cluster showed low sequence homology with pathogenic strains. The wza is a highly conserved gene in the cps cluster that encodes an outer membrane protein. A non-capsulated mutant was constructed by deletion of wza. Phenotype studies demonstrated that non-capsulated cells were less buoyant and easy to sediment. The transformation efficiency of the non-capsulated mutant reached 6.4 × 10 CFU μg DNA, which is 10 times higher than that of the wild strain. 52.2 g 1,3-propanediol L, 30.7 g 2,3-butanediol L, and 175.9 g 2-ketogluconic acid L were produced by non-capsulated mutants, which were 10-40% lower compared to wild strain. Furthermore, viscosities of the three fermentation broths decreased to approximately 1.3 cP from the range of 1.8-2.2 cP.
Non-capsulated K. pneumoniae mutants should allay concerns regarding biological safety, improve transformation efficiency, lower viscosity, and subsequently ameliorate the financial burden of the downstream process of chemicals production.
研究肺炎克雷伯菌荚膜缺失对细胞转化效率及1,3 - 丙二醇、2,3 - 丁二醇和2 - 酮基葡萄糖酸产量的影响。
cps基因簇与致病菌株的序列同源性较低。wza是cps簇中一个高度保守的基因，编码一种外膜蛋白。通过缺失wza构建了无荚膜突变体。表型研究表明，无荚膜细胞浮力较小，易于沉降。无荚膜突变体的转化效率达到6.4×10 CFU μg DNA，比野生菌株高10倍。无荚膜突变体产生了52.2 g/L 1,3 - 丙二醇、30.7 g/L 2,3 - 丁二醇和175.9 g/L 2 - 酮基葡萄糖酸，与野生菌株相比降低了10 - 40%。此外，三种发酵液的粘度从1.8 - 2.2 cP降至约1.3 cP。
无荚膜肺炎克雷伯菌突变体应能减轻对生物安全的担忧，提高转化效率，降低粘度，并随后减轻化学品生产下游工艺的经济负担。
