‘赞皇枣’黑腐病菌拮抗芽胞杆菌的筛选及发酵条件优化

In vitro screening of antagonistic Bacillus against Alternaria alternata and optimization of fermentation factors

以‘赞皇枣,黑腐病主要病原菌链格孢菌[Alternaria alternata （Fries） Keissler]为靶标,对具有较强抗真菌活性的10株芽胞杆菌进行室内多重筛选,并采用二次回归正交旋转设计和单因素试验对筛选获得的目标菌分别进行发酵培养基优化和最佳发酵条件确立.结果表明：芽胞杆菌B07对靶标菌拮抗作用良好,活体拮抗抑菌带宽度达（8.00±0.50）mm,无菌发酵滤液抑菌圈直径为（24.44±1.37）mm,且有良好的持久性,具有开发应用价值;B07发酵的最优培养基为：红薯粉2 g/L,牛肉膏10 g/L,NaCl 10 g/L,MnSO40.02 g/L;最佳发酵条件为：种子液浓度1.5×107～2.0×108cfu/mL时,接种量5％（V/V）,装液量40 mL/250 mL,原始pH7.0,发酵温度32℃,时间72h.

Multiple in vitro screening of 10 Bacillus strains against Alternaria alternata （Fries） Keissler was conducted.The optimum fermentation medium and fermentation conditions for the selected strain were determined by using quadratic orthogonal rotation combination design and single-factor experiment design,respectively.The results showed that the strain Bacillus B07 had obvious and stable antagonistic effect on A.alternata.The inhibition belt of the living body was up to （8.00±0.50）mm in width,and the inhibition zone of the bacteria-free filtrate was （24.44± 1.37）mm in diameter.With lasting inhibition effect,Bacillus B07 had great potential for a commercial development.The optimum fermentation medium for strain B07 consisted of 2 g/L sweet potato powder,10 g/L beef extract,10 g/L NaCl,and 0.02 g/L MnSO4.The optimum fermentation conditions were defined as follows：inoculation amount,5% （V/V） with a seed broth concentration of 1.5 × 107-2.0 × 108 cfu/mL,40 mL media in a 250 mL flask,initial pH at 7.0,and fermentation at 32 ℃ for 72 h.