中国苏芸金芽孢杆菌肯尼亚亚种Ag株发酵工艺条件研究

Fermentation process of bacillus thuringiensis subsp kenya Ag strain

目的 开发具有特异性杀虫谱特性的Bt菌新株系。方法 在对摇瓶培养研究的基础上 ,通过改变培养基成分、通气量和pH等操作条件 ,检测不同条件对菌体生长量、芽孢及伴孢晶体形成的影响 ,研究中国苏芸金芽孢杆菌肯尼亚亚种Ag株 (BtKen Ag)发酵罐间歇发酵的工艺条件。结果 中国BtKen Ag发酵罐发酵最佳工艺条件 :发酵温度维持 3 0℃ ,发酵前期 ,控制pH为 7 0 ,用较大的通气量 1∶2 0V/(V·min) ;发酵后期不控制pH ,并适当减小通气量为 1∶0 5V/(V·min)。发酵前期菌体达到 7 5× 1 0 10 /ml的较高浓度 ,发酵后期菌体向芽孢转化的转化率高达 98%以上。结论 初步得出适于该菌间歇发酵的最佳工艺 ,为该菌制剂的应用提供可靠依据。

Objective To develop new strains of bacillus thuringiensis with specific insecticidespectrun. Methods On the basis of formentation in shaking culture,the effects of changes in bioreactor operations, such as concentration of glucose, aeration and pH value,on the growth and sporulation of bacillus thuringiensis subsp kenyae Ag strain were studied. Results The optimum culture conditions are as follows: temperature 30℃, pH 7.0, aeration 1∶2.0 V/(V·min) in the earlier stage,and no controll of pH, aeration 1∶0.5 V/(V·min) in the later periold. The number of cells reached 7.5×10 9/ml and spore forming rate was over 98%. Conclusions The optimum technology, obtained from the batch cultivation, provides basis for applying the preparation of bacillus thuringiensis subsp.kenyae Ag strain.