响应面法优化生防暹罗芽孢杆菌JZ1-4-10的发酵参数

Optimization of fermentation parameters against Bacillus siamensis JZ1-4-10 by response surface method

【目的】优化暹罗芽孢杆菌JZ1-4-10的发酵培养基组分配比和发酵条件,以提高其对马铃薯干腐病菌的抑菌活性,为后续相关生防制剂的工业开发及农业应用打下理论基础。【方法】通过单因素试验筛选菌株JZ1-4-10生长的最佳碳源、氮源、无机盐及适宜浓度,通过响应面法获得菌株JZ1-4-10的最佳发酵培养基组分配比,在此基础上优化菌株JZ1-4-10的发酵温度、pH、接种量、装液量和摇床转速等发酵条件。【结果】菌株JZ1-4-10的最佳碳源、氮源和无机盐分别为玉米粉、大豆蛋白胨和KCl。以玉米粉(A)、大豆蛋白胨(B)和KCl(C)为因变量,菌株JZ1-4-10对马铃薯干腐病病原菌茄病镰刀菌的抑菌活性为响应值,拟合得到菌株JZ1-4-10抑菌率(y)的二次多项回归方程为y=64.02+0.4937A+2.31B-2.19C-1.17AB+138AC-1.81BC-4.73A2-4.58B2-3.86C2,其中,玉米粉、大豆蛋白胨和KCl间的交互作用对菌株JZ1-4-10抑菌活性的影响均达显著水平(P<0.05),尤其玉米粉与KCl及大豆蛋白胨与KCl的交互作用对抑菌活性的影响达极显著水平(P<0.01)。响应面分析优化得到菌株JZ1-4-10的最佳发酵培养基组分配方:玉米粉0.94%、大豆蛋白胨1.23%、KCl 0.72%,且该条件下菌株JZ1-4-10的抑菌活性的实际值为65.20%,与试验预测的64.63%非常接近。经单因素优化后菌株JZ1-4-10的最佳发酵条件为装液量90 mL/250 mL、接种量1.5%、摇床转速160 r/min、培养温度30℃、pH 7。【结论】优化后的培养基提高了菌株JZ1-4-10的产孢量和抑菌活性,优化的发酵方案可用于快速、大批量培养菌株JZ1-4-10菌悬液。

【Objective】The study aimed to optimize the fermentation culture medium composition formulation and conditions of Bacillus siamensis JZ1-4-10 to improve its antibacterial activity against potato dry rot bacteria,laying a foundation for the subsequent industrial development and agricultural application of related biocontrol agents.【Method】The optimal carbon source,nitrogen source,inorganic salt and suitable concentration of B.siamensis JZ1-4-10 were screened by the single factor test.The optimal fermentation culture medium composition formulation of B.siamensis JZ1-4-10 was obtained using response surface methodology.Based on these findings,the fermentation conditions such as fermentation temperature,pH,inoculation amount,liquid volume and rotational speed of strain JZ1-4-10 were opti mized.【Result】The optimal carbon source,nitrogen source and inorganic salt of B.siamensis JZ1-4-10 were corn flour,soy peptone and KCl respectively.With corn flour(A),soy peptone(B)and KCl(C)as the dependent variables,and the antibacterial activity of B.siamensis JZ1-4-10 against the potato dry rot pathogen Fusarium solani as the response value,the quadratic multiple regression equation obtained for the inhibition rate(y)of B.siamensis JZ1-4-10 was y=64.02+0.4937A+2.31B-2.19C-1.17AB+138AC-1.81BC-4.73A2-4.58B2-386C2.The interactions among corn flour,soy peptone and KCl significantly influenced the antibacterial activity of B.siamensis JZ1-4-10(P<0.05),especially the interactions between corn flour and KCl and between soy peptone and KCl were extremely significant(P<0.01).The optimum propor tion of fermentation culture medium composition formulation by response surface analysis for B.siamensis JZ1-4-10 were as follows:0.94%corn flour,1.23%soy protein and 0.72%KCl.Under this condition,the actual value of antibacterial activity of B.siamensis JZ1-4-10 was 65.20%,which was very close to the predicted value of 64.63%.Similarly,the opti mal fermentation conditions optimized by single factors of B.siamensis JZ1-4-10 were liquid volume of 90 mL/250 mL,inoculation amount of 1.5%,rotational speed of 160 r/min,culture temperature of 30℃,and pH of 7.【Conclusion】The optimized culture medium enhances the sporulation and antibacterial activity of B.siamensis JZ1-4-10,the optimized fermentation method can be used to culture the suspension of strain JZ1-4-10 in fast speed and by large amount.