苏云金芽孢杆菌WB9菌株的分离、生化特性及培养基优化

Isolation,biochemical characteristics and optimization of media of Bacillus thuringiensis WB9

对来自武夷山自然保护区非耕作区的200个土壤样品进行了苏云金芽孢杆菌的分离,获得12株菌株,分离频率为6.0%.室内感染力测定结果表明WB9菌株对小菜蛾具有高感染力、对甜菜夜蛾具有较高的感染力.生理生化指标测定结果显示WB9与库斯塔克亚种8010的反应表现型相同,仅在个别反应上有强弱差异,由此推测WB9可能属库斯塔克亚种.此外,通过正交试验设计和室内摇瓶培养,获得了优化的WB9工业培养基组合,即30.0 g.L-1玉米淀粉、20.0 g.L-1黄豆饼粉、15.0 g.L-1玉米粉、10.0 g.L-1酵母粉、2.0 g.L-1蛋白胨、15.0 g.L-1玉米浆、5.0 g.L-1CaCO3、0.3 g.L-1MgSO4.7H2O、1.0 g.L-1KH2PO4和0.02 g.L-1ZnSO4.7H2O.

Bacillus thuringiensis was isolated from 200 soil samples collected from Wuyi mountain in southern China. Twelve Bt strains were obtained and the isolation frequency was 6.0%. Bioassay showed that WB9 was highly and moderately toxic to Plutella xylosteUa and Spodoptera exigua, respectively. The results of biochemical reactions indicated that the presentations of WB9 and 8010 were the same. Thus, it could be deduced that the potential status of serovar of WB9 was kurstaki. In addition, an orthogonal design was selected to arrange batch fermentation in shaker flasks to carry out the optimization of media of WB9 strains. The optimal combi- nation comprising 30.0 g·L^-1 of corn meal, 20.0 g·L^-1 of soybean powder, 15.0 g · L^-1 of corn powder, 10.0 g · L^-1 of yeast powder, 2.0 g · L^-1 of peptone, 15.0 g · L^-1 of corn syrup, 5.0 g · L^-1 of CaCO3,0.3 g · L^-1 of MgSO4 · 7H2O, 1.0 g · L^-1 of KH2PO4 and 0.02 g · L^-1 of ZnSO4 · 7H2O was obtained.