苏云金芽孢杆菌A322菌株发酵培养基和发酵条件的优化

Optimization of Bacillus thuringiensis A322 Strain Fermentation Medium and Cultural Conditions

以菌体生长对数末期发酵液OD600值为优化标准,通过单因素和正交试验方法对前期室内实验筛选得到的对棉铃虫(Helicoverpa armigera Hubner)有较高活性的苏云金芽孢杆菌Bt A322菌株进行培养基优化,并进行发酵。结果表明,最佳培养基配方为0.5%黄豆粉+0.5%酵母粉+0.5%葡萄糖+0.5%胰蛋白胨+0.2%碳酸钙+0.1%磷酸二氢钾+0.1%硫酸镁。最佳培养条件为培养时间20 h,初始p H值7.5,发酵温度30℃,摇床转速为200 r·min-1,接种量3%,250 m L三角瓶适宜装35 m L培养基。优化后的菌体生长量OD600值比优化前的提高了44.7%。

Bacillus thuringiensis Berliner strain A322 with higher activity against Helicoverpa armigera Hubner screened indoor was cultured on media through single-factor and orthogonal experiment to optimize cultural medium based on the optimization standard of OD600 of the fermented liquid of B.thuringiensis at the late logarithmic phase.The optimum medium is 0.5% soybean meal,0.5% yeast extract,0.5% glucose,0.5% tryptone,0.2% calcium carbonate,0.1% potassium dihydrogen phosphate,and 0.1% magnesium sulfate.The major factors in laboratory shake flask liquid fermentation,such as initial pH,temperature,speed,etc were determined.The optimum cultural conditions are found to be incubation time 20 h,pH7.5,fermentation temperatures 30 ℃,speed 200 r · min^-1,inoculum size 3%,and medium volume 35 mL in a 250 mL flask.The OD600 value of the bacterial growth was increased by 21.9% after optimization of the cultural conditions.