一株烟草青枯病生防菌的筛选鉴定及其发酵优化

Screening and Fermentation Optimization of Antagonistic Bacillus against Tobacco Bacterial Wilt

以烟草青枯病原菌[茄科雷尔氏菌(Ralstonia solanacearum)]为筛选指示菌,采用平板共培养初筛和发酵上清滤液复筛的方法,筛选到烟草青枯病拮抗菌株XLA03,其抑菌圈直径为13.74 mm;经16S rDNA鉴定,菌株XLA03为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。由单因素试验和正交试验优化得到了菌株XLA03生物量较高的摇瓶发酵培养基配方为玉米淀粉15.0 g/L、豆粕50.0 g/L、K2HPO4·3H2O 1.0 g/L、MgSO4·7H2O 0.75 g/L、MnSO4·H2O 0.010 g/L;培养条件为起始pH 7.0,接种量1%,装液量20 mL/250 mL。

One bacterial strain was screened for its antagonistic activity against Ralstonia solanacearum based on the size of the bacteriostatic circle in vitro by the dual culture and culture filtrate tests,and named as XLA03. Its bacteriostatic circle could reach 13 mm. According to determination and analysis of 16S rDNA, the strain XLA03 was identified as Bacillus amyloliquefaciens. Based on the single factor experiments and orthogonal experiments, an optimal fermentation medium for its biomass-production in flasks was composed of maize starch 15.0 g∕L, soybean meal 50.0 g∕L,K2HPO4·3H2O 1.0 g∕L,MgSO4·7H2O 0.75 g∕L,MnSO4·H2O 0.01 g∕L. The optimal fermentation condition was initial pH of 7.0, inoculum size of 1% loaded liquid of 20 mL∕250 mL.