过表达生长相关基因对肺炎克雷伯氏菌甘油代谢的影响

Effects of growth-related gene overexpression on glycerol metabolism in Klebsiella pneumoniae

在肺炎克雷伯氏菌(Klebsiella pneumoniae)中过表达生长调控基因,以携带空载体的重组菌为对照,筛选生物量高且目标产物增加的重组菌。摇瓶发酵24 h后测定各重组菌的生物量、甘油消耗及代谢物产量。研究发现,与携带空载体的重组菌相比,过表达编码核糖ABC转运酶的rbs C基因可使生物量和甘油转化率分别提高16.08%和24.69%,1,3-丙二醇和2,3-丁二醇产量分别提高39.59%和19.79%;过表达tRNA核苷酸转移酶基因cca可使生物量和甘油转化率分别提高7.17%和19.16%,1,3-丙二醇和2,3-丁二醇产量分别提高36.24%和13.39%。研究结果表明刺激细菌生长可望促进目标产物的积累。

A total of eight endogenous growth-related genes have been overexpressed in Klebsiella pneumoniae in order to determine which of them substantially facilitates cell growth and increases the biosynthesis of desired metabolites including 1,3-propanediol （1,3-PD） and 2,3-butanediol （2,3-BD）. By measuring the biomass, glycerol consumption, and the amounts of the desired metabolites of the recombinant K. pneumoniae strains grown in shake flasks, we found that overexpression of the ABC transport enzyme gene rbsC led to faster cell growth and enhanced production of metabolites compared with the strain harboring empty vector. The biomass, glycerol conversion ratio, 1,3-PD and 2,3-BD concentrations increased by 16.08% , 24.69% , 39.59% and 19.79% , respectively. For the recombinant K. pneumoniae strain overexpressing the tRNA nucleotidyltransferase gene cca, the biomass, glycerol conversion ratio, 1,3-PD and 2,3-BD increased by 7.17% , 19. 16% , 36.24% and 13.39% , respectively. Overall these results indicated that stimulating cell proliferation enhances the production of desired metabolites.