营养因子对苏云金芽胞杆菌4.0718 产杀虫蛋白Cry1和Cry2的影响

Nutrition Factors Influence the Production of Insecticidal Crystal Proteins Cry1 and Cry2 from Bacillus thuringiensis 4.0718

摘要:

为了提高杀虫蛋白Cry1和Cry2产量, 首先采用Plackett-Burman设计筛选出发酵培养基中影响苏云金芽胞杆菌4.0718表达毒蛋白Cry1的显著性因子为黄豆饼粉和MnSO4?H2O, Cry2的产量在该配方中无显著性影响因子。然后利用最速上升实验逼近Cry1最大产出区域, 找到后续试验中心点。最后通过响应面优化得到黄豆饼粉和MnSO4?H2O的最佳浓度为11.5 g/L和0.02 g/L, 使Cry1和Cry2产量分别达到0.32 mg/mL和0.11 mg/mL, 比原优选配方产量提高了两倍多。该优化配方发酵液对棉铃虫的半致死浓度(LC50)为1.09 μL/mL, 杀虫活性比原优化配方显著提高。

Abstract:

In order to increase the production of insecticidal crystal proteins Cry1 and Cry2, firstly, Plackett-Burman design was applied to evaluate the effectiveness of the related nutrition factors; it was found that the soybean powder and MnSO4·H2O were significant factors for Cry1 production, but the yield of Cry2 wasn’t effected remarkably in such medium. Then the steepest ascent experiment was adopted to approach the optimal region of the medium composition. Lastly, the optimal concentration of the soybean powder and MnSO4·H2O was 11.5 and 0.02 g/L, obtained by response surface methodology (RSM). The final yields of Cry1 and Cry2 was 0.32 mg/mL and 0.11 mg/mL, increasing twice more than that in the medium optimized before. The median lethal concentration (LC50) of optimal medium was 1.09 μL/mL. The toxicity to Helicoverpa armigera was significantly enhanced than the old one.