萎缩芽胞杆菌HMB22922发酵工艺及其制剂研制

Fermentation and Preparation Technology of Bacillus atrophaeus HMB22922

萎缩芽胞杆菌Bacillus atrophaeus HMB22922是一株有效防治棉铃疫病的生防细菌。为降低该菌株的生产成本和提高其制剂的适用性,本研究完善了该菌株的发酵工艺并筛选出用于可湿性粉剂加工的适宜助剂。通过对11种规模化生产所用培养基进行筛选,确定2号培养基作为初始培养基;采用正交试验设计对其进行优化,结果表明,黄豆粉、酵母粉、玉米粉及碳酸钙是影响该菌株发酵活菌数的主效因素,最佳用量分别为13、3、30和3g/L。进一步确定发酵液初始pH值为7.0、培养温度30℃为该菌株的适宜培养条件,发酵活菌数达到2.81×10^9cfu/mL。分别以润湿时间和悬浮率为指标,筛选该菌株可湿性粉剂所需助剂,结果表明,采用粉状885增效助剂B型和SP-2836作为润湿剂和分散剂,其可湿性粉剂润湿分散性能最优,并确定2.00×10^9cfu/g萎缩芽胞杆菌HMB22922可湿性粉剂配方。该制剂防治棉铃疫病的室内评价结果表明,人工接种棉铃疫病病原菌7 d后,该制剂能显著降低棉铃疫病的病情指数,防效达52.16%。

Bacillus atrophaeus HMB22922 exhibited strong inhibitory activity against the growth of Phytophthora boehmeriae,which caused cotton boll blight.With the purpose of reducing the production cost of B.atrophaeus HMB22922 as well as improving the applicability of preparation made of HMB22922,the fermentation technology for strain HMB22922 was optimized and suitable inert ingredients for wettable powder(WP)were screened.Medium NO.2 was selected from eleven industrial fermentation media and used as the initial medium,then the media components were further optimized by orthogonal test in shake-flask fermentation.Results showed that soybean flour,yeast extract,corn meal and CaCO3 were the principal factors affecting the yield of HMB22922,and the optimum dosage of these 4 factors was 13,3,30 and 3 g/L,respectively.The optimal initial pH value was 7.0 and the culture temperature was 30℃.Under the optimized culture condition,the number of viable bacteria could reach 2.81×10^9 cfu/mL.Using the wetting time and suspension rate as indexes,the auxiliaries for HMB22922 were screened.Results showed that the 885 synergistic type B and SP-2836 could be used as the suitable wetting agent and dispersant for HMB22922 WP,and the formula of 2.00×10^9 cfu/g HMB22922 WP was developed.Control efficacy of the preparation against cotton boll blight was evaluated in the growth chamber.Result showed that the 20-fold dilution of the prepared WP could significantly reduce the disease index,and the control efficacy was 52.16%at 7 days after inoculation with pathogen.