草莓根腐病拮抗芽孢杆菌Z-14菌株发酵培养基的优化

Optimization of fermentation medium of antagonistic bacteria Bacillus sp.Z-14 strain against strawberry root rot

采用Plackett-Burman试验设计对影响草莓根腐病拮抗芽孢杆菌Z-14菌株芽孢产量的8种营养元素进行显著性筛选,获得培养基成分中3个重要影响因子:MnSO4·H2O、酵母粉和玉米粉。用最陡爬坡路径法获得3种因子的最适浓度范围,利用Box-Behnken试验设计及响应面分析法研究主要影响因素的最佳条件,确定Z-14菌株最佳芽孢产量培养基组成为MnSO4·H2O 0.061%、酵母粉1.99%、玉米粉0.965%、NaH2PO4·2H2O0.2%、Na2HPO4·2H2O 0.4%,优化后芽孢产量达1.91×109 cfu/mL,与预测芽孢产量1.83×109 cfu/mL接近,表明该模型能较好预测芽孢的实际产量。

Plackett-Burman experimental design was used for significance screening of eight kinds of nutrients affecting the spores yield of strawberry root rot antagonistic bacreria Bacillus sp.Z-14 strain and three important factors of medium composition obtained were MnSO4·H2O,yeast extract and corn flour.The pass of steepest ascent was undertaken to approach the optimal response region of the three significant factors.Box-Behnken design and response surface analysis were adopted to further investigate the mutual interaction between the variables and identify optimal values that bring maximum spore yield.The optimal culture medium of Z-14strain was as follows：MnSO4·H2O 0.061%,yeast extract 1.99%,corn flour 0.965%,NaH2PO4·2H2O 0.2%,Na2HPO4·2H2O 0.4%.The spore yield reached 1.91×10^9 cfu/mL after fermentation experiment under optimal condition and basically consistent with the theoretical value about 1.83×10^9 cfu/mL,which indicated that the model can predict the actual spores yield.