香蕉枯萎病拮抗菌株BS11抗真菌活性物质的研究

Analysis on Antifungal Substance from Bacillus subtilis BS11

[目的]对枯草芽孢杆菌BS11抗真菌活性物质进行研究,为该菌株的进一步开发应用提供参考。[方法]比较了枯草芽孢杆菌BS11在LB和NB培养基上的生长情况,比较了3种方法提取该菌株活性物质的效果,并探讨了该菌株的最佳培养条件。[结果]以香蕉枯萎病菌为指示菌,发现拮抗菌在LB和NA 2种不同培养基中有很明显的差别,LB培养基中生长繁殖速度快,但上清液活性很低,NA培养基中繁殖速度较慢,上清液活性却较好;乙醇沉淀法和乙酸乙酯萃取法均不能提取到活性物质,硫酸铵沉淀法基本上可将活性物质提取出来;BS11最佳的培养条件为初始p H7,温度30℃,通气量60 ml;发酵上清液有蛋白酶、纤维素酶活性,但没有几丁质酶活性。[结论]枯草芽孢杆菌BS11株所产的抗真菌活性物质具有性质稳定、广谱、易于提取等优点,为其应用于植物病害防治提供了理论依据。

[Objective] Antifungal substance from B.subtilis BS11 was studied to provide reference for further development and application.[Method] Growth conditions of B.subtilis BS11 in LB and NB broth were compared; effects of three methods for extracting antifungal substance from B.subtilis BS11 were compared; the optimal fermentation conditions of antifungal substance production were studied.[Result] Fusarium.oxysporum f.sp.Cubense was as the indicator,the B.subtilis BS11 had obvious difference in antifungal bioactivity and growth rate in LB and NA mediums,and it was stronger in NB broth than in LB broth,but grew faster in LB broth than in NB broth.Ethanol and ethyl acetate could not extract antifungal substances,and antifungal factor from BS11 was further identified as a kind disease-resistance protein by ammonium sulfate precipitation method.The optimums fermentation conditions of antifungal substance production were original pH7.0,fermentation temperature 30 ℃and amount of load 60 ml （in 250 ml flask）.The degrading test showed that the supernatant had protease activity and cellulase activity but didn t have chitinase activity.[Conclusion] The results provide theoretical basis for application of BS11 in controlling plant diseases.