响应面法优化提高萎缩芽孢杆菌E20303抑制马铃薯干腐病病原菌活性的研究

Improving the activity of Bacillus atrophaeus E20303 against the dry rot pathogen of potato: based on response surface methodology

摘要:

【背景】萎缩芽孢杆菌E20303可以有效地抑制马铃薯干腐病病原菌的活性，而响应面法可在较少的试验次数下优化生防菌发酵培养基配方与发酵条件，获得的最优组合将为马铃薯干腐病生防菌剂的制备与应用提供参考。【目的】以分离自青海察尔汗盐湖湖泥中且对马铃薯干腐病病原菌具有较高抑菌活性的萎缩芽孢杆菌E20303为研究对象，利用响应面法对其培养基配方和发酵条件进行优化，以期提高其对马铃薯干腐病病原菌的抑菌活性。【方法】采用单因素试验、中心组合设计试验及响应面法设计优化萎缩芽孢杆菌E20303发酵培养基配方及发酵条件。【结果】培养基最优发酵配方(g/L)：淀粉10.72、酵母粉23.60、七水合硫酸镁16.00、碳酸钙1.14、磷酸二氢钾8.00和磷酸氢二钾16.00，优化后抑菌率由46.51%提高至62.00%；最优发酵条件为装液量102.89 mL、pH 8.64、温度28.73℃、转速200 r/min、培养时间3 d、接种量2%，优化后抑菌率由51.15%提高至72.51%。【结论】实验获得了对马铃薯干腐病病原菌的抑菌活性明显提高的萎缩芽孢杆菌E20303发酵配方及发酵条件，为马铃薯干腐病生防制剂的后续研究提供支撑。

关键词:响应面法;发酵配方;发酵条件;萎缩芽孢杆菌;马铃薯干腐病;抑菌活性

Abstract:

[Background] Bacillus atrophaeus E20303 can inhibit the activity of the dry rot pathogen of potato and the response surface methodology can optimize the components of medium for fermentation and fermentation conditions of biocontrol bacteria. The optimal medium components and fermentation conditions for E20303 can serve as a reference for the preparation and application of biocontrol agents against potato dry rot. [Objective] To optimize the medium components and fermentation conditions of E20303, a strain isolated from the mud of Chaerhan Salt Lake in Qinghai with high activity against the dry rot pathogen of potato, by response surface methodology in order to improve its antifungal activity. [Methods] Single factor experiment, central composite design, and response surface methodology were used to design and optimize the medium components and fermentation conditions of E20303. [Results] The optimal components of the medium were starch 10.72 g/L, yeast powder 23.60 g/L, MgSO₄·7H₂O 16.00 g/L, CaCO₃ 1.14 g/L, KH₂PO₄ 8.00 g/L, and K₂HPO₄ 16.00 g/L. After optimization, the antifungal rate increased from 46.51% to 62.00%. The optimal fermentation conditions were liquid medium volume of 102.89 mL, pH 8.64, 28.73 ℃, rotation speed 200 r/min, culture for 3 days, and inoculum 2%. Under the conditions, the bacteriostatic rate rose from 51.15% to 72.51%. [Conclusion] The fermentation formula and fermentation conditions of E20303 with significantly improved activity against the dry rot pathogen of potato were clarified, which laid a foundation for research on the biocontrol agents against potato dry rot.

Key words:response surface methodology;fermentation medium formula;fermentation conditions;Bacillus atrophaeus;potato dry rot;antifungal activity