青枯病和根肿病生防细菌BS2004的发酵培养基和培养条件优化

解淀粉芽孢杆菌BS2004是一株对不同生化型的番茄青枯病菌Ralstonia solanacearum和十字花科根肿病菌Plasmodiophora brassicae具有抑制作用的优良生防菌,主要依靠产生拮抗物质抑制病菌.为提高其抑菌活性物质的产量与防治效果,本文采用正交试验和单因素试验设计,通过摇瓶培养对其发酵培养基和培养条件进行了优化.优化后的发酵培养基配方为蛋白胨 10 g·L^-1、牛肉浸膏 1 g·L^-1、酵母粉 1 g·L^-1和Nacl 8 g·L^-1;优化后的培养条件为pH 7.5、温度 35 ℃、装瓶量 35 mL·50 mL^-1、接种量 3%（v/v）和最佳培养时间 24 h.经条件优化后培养的 BS2004对青枯病菌的抑菌圈直径达 21.75 mm,对番茄青枯病的防治效果达 80%,对十字花科根肿病的防治效果达 60%,增产 1.92 倍.

Optimization of Medium and Cultural Conditions for Biocontrol Bacterial Strain BS2004 against Ralstonia solanacearum and Plasmodiophora brassicae

Antagonistic Bacillus amyloliquefaciens BS2004 was a promising biocontrol agent against various biotypes of Ralstonia solanacearum and Plasmodiophora brassicae by largely producing antagonistic substances. To improve the yield of its active substances and control effect, the medium and cultural conditions of strain BS2004 were optimized by orthogonal design method and single factor tests in shake-flask. Results showed that the optimal medium were composed of 10 g peptone, beef extract 1 g, yeast extract 1 g, and NaC1 8 g in 1 L medium. The optimal cultural conditions were as follows： initial pH 7.5, temperature 35 ℃, medium volume 35 mL in 50 mL flask, inoculum volume 3% （v/v） and fermentation time 24 h. Under the conditions, the diameter of inhibition zone between the bacteria and R. solanacearum reached 21.75 mm and control effect of the strain against tomato bacterial wilt reached 80%. The control effect of strain BS2004 against crucifer club root disease was up to 60% and the yield increased 1.92 times.