拮抗菌株xj063-1发酵条件的优化及室内防效测定
Optimization and fermentation conditions of antagonistic strain xj063-1 and its effect on jujube black spot

为探讨菌株xj063-1的最优发酵条件,以菌体生物量和对病原菌的抑制率为指标,采用单因素方法对菌株的发酵条件进行优化,并将优化的发酵液在离体枣果上进行防效测定。结果表明,当装液量为50 mL时,拮抗菌株生物量OD600为1.987,对病原菌的抑制率为67.1%;接种量为装液量体积的4%时,生物量OD600为1.573,对病原菌的抑制率为59.7%;初始pH 7.0时,其OD600为1.905,对病原菌的抑制率为65.6%;温度在30℃、转速180 r/min时,OD600 分别为1.969和1.982,对病原菌的抑制率分别为62.2%和61.2%。拮抗菌株优化后的发酵液通过预防法处理后的枣果的病斑面积为4 mm2,对照发病面积为121 mm2,抑制率为96.7%;通过治疗法处理后的枣果的病斑面积为12.25 mm2,抑制率为89.9%,表明菌株xj063-1具有较好的生防潜力。
In order to investigate best conditions for fermentation liquid of antagonistic strain xj063-1, the single factor experiments were performed with bacterial biomass and the inhibition rate of pathogenic bacteria as indicators. The results showed that the optimal fermentation conditions were composed of the following factors: liquid volume, 50 mL; inoculum, 4% (v/v); initial pH 7.0; fermentation temperature, 30℃; rotation speed, 180 r/min. Bacterial biomass OD600 and the inhibition rate of pathogenic bacteria were 1.987/67.1%, 1.573/59.7%, 1.905/65.6%, 1.969/62.2% and 1.982/61.2%, respectively. When optimized filtrate was treated on jujube fruits, the lesion diameters were 4 mm2 by prevention, and 12.25 mm2 by therapy, respectively. The control effects were 96.7% by prevention and 89.9% by therapy, respectively. These results indicated that the antagonistic strains may provide a new biological control method in controlling Alternaria alternate.