松树内生蜡样芽孢杆菌NJSZ-13菌株发酵培养基及条件优化

Optimization of Medium and Culture Conditions for Bacillus cereus NJSZ-13

为了进一步开发蜡样芽孢杆菌Bacillus cereus NJSZ-13菌株对松材线虫病的生物防治潜能,提高该菌的利用率,为后期蜡样芽孢杆菌NJSZ-13粉剂的工艺生产做准备,本研究通过单因素和正交试验对该菌株进行了发酵培养基和摇瓶发酵条件的优化。培养基优化单因素试验结果显示,培养基最佳碳源为可溶性淀粉,最佳氮源为大豆蛋白胨,最佳无机盐为CaCl2;将可溶性淀粉、大豆蛋白胨和CaCl2(C)三因素按L9(33)设计正交试验,结果表明,最佳配比为:可溶性淀粉10 g·L^-1,大豆蛋白胨14 g·L^-1,CaCl26 g·L^-1。发酵条件优化结果表明,最佳发酵温度为28℃;最佳发酵初始pH值为7.5;最佳接种量为2%;最佳装液量为30%。与优化前的培养条件相比,在该优化条件下,摇瓶发酵单位体积发酵液中的菌株活菌数量达到4.10×10^9 cfu·mL^-1,是优化前单位体积发酵液中活菌数量的4.1倍,达到了菌体富集的目的。

In order to research the biocontrol of Bacillus cereus NJSZ-13 strain against pine wilt disease,single factor and orthogonal experiments were conducted on optimization of medium and culture conditions.Single factor tests showed that the best carbon source in the medium was soluble starch,nitrogen source was soy peptone,and inorganic salt was calcium chloride.Orthogonal test demonstrated that the optimum proportion was:soluble starch 10 g/L,soy peptone 14 g/L,calcium chloride 6 g/L.The experiment resulted that the optimal culture conditions were:fermentation temperature at 28℃,initial pH of 7.5;inoculum size of 2%and liquid volume of 30%.Compared with the culture conditions before optimization,viable count of strain NJSZ-13 in fermentation broth under the optimized conditions reached 4.10×10^9 cfu/mL,4.1 times of that before one.