枯草芽孢杆菌S37沼液发酵培养基优化及其产物对棉苗立枯病的防治

为获得以沼液为基础的枯草芽孢杆菌S37的最佳发酵培养基。采用Plackett Burman法和响应面(Response Surface Methodlolgy, RSM)对以沼液为基础的枯草芽孢杆菌S37抑菌蛋白的发酵培养基进行优化。在Plackett Burman试验基础上确定对抑菌蛋白影响较大的4个显著因素：MgSO₄·7H₂O、玉米粉、KH₂PO₄和豆粕；通过最陡爬坡试验，中心组合设计及响应面分析确定枯草芽孢杆菌S37的最优发酵培养基组成：MgSO₄·7H₂O 2.95 g·L^-1、(NH₄)₂SO₄ 2.4 g·L^-1、NaCl 3.0 g·L^-1、KNO₃ 4.41 g·L^-1、CaCO₃ 5.89 g·L^-1、ZnCl₂ 1.11 g·L^-1、玉米粉4.18 g·L^-1、KH₂PO₄ 4.14 g·L^-1和豆粕2.79 g·L^-1。在优化条件下进行发酵验证，试验值和预测值较接近，吻合度较高，相对误差较小，枯草芽孢杆菌抑菌圈达1.94 cm，比优化前提高8.38%；用此培养基发酵产物滴施棉苗根际土壤，与对照相比，相对防效达到45.94%。

Fermentation Optimization of Bacillus subtilis S37 Based on Biogas Liquid and Controlling Cotton Rhizoctoniosis by Its Products

To get the best fermentation medium of Bacillus subtilis S37 on the basis of biogas liquid, Response Surface Methodology is used to optimize the culture components for the antifungal activity by Bacillus subtilis S37. Plackett Burman Design is used to evaluate the four process factors relevant to the antifungal activity, including MgSO₄·7H₂O, corn flour, KH₂PO₄ and soybean meal. The path of steepest ascent is used to approach the optimal region of the antifungal activity medium subsequently. Finally, the concentrations of these factors are determined by Central Composite Rotatable Design and Response Surface Analysis. The optimized conditions are: MgSO₄·7H₂O 2.95 g·L^-1,(NH₄)₂SO₄ 2.4 g·L^-1, NaCl 3.0 g·L^-1, KNO₃ 4.41 g·L^-1, CaCO₃ 5.89 g·L^-1, ZnCl₂ 1.11 g·L^-1, corn flour 4.18 g·L^-1, KH₂PO₄ 4.14 g·L^-1and soybean meal 2.79 g·L^-1. Under these conditions, the fermentation validation shows that the experimental value is comparable to model prediction, having high inosculating degree and the difference was relatively small. The antifungal zone is 1.94 cm, which is 8.38% higher than it was before optimization. The fermentation product was drip irrigated to cotton rhizosphere soil for control cotton Rhizotoniosis. The control effect is 45.94%.