生防枯草芽孢杆菌B29菌株抗菌物质的初步研究

Antifungal Substance from Biocontrol Bacillus subtilis B29 Strain

通过检测生防枯草芽孢杆菌除菌上清液对黄瓜枯萎病菌Fusarium oxysporium f．cumerinum菌丝生长和分生孢子萌发的抑制作用，初步研究了生防枯草芽孢杆菌B29菌株抗菌物质的活性。结果表明，枯草芽孢杆菌B29菌株分泌的抗菌物质不仅抑制病原菌的生长；并可抑制尖孢镰刀菌孢子的萌发，使分生孢子萌发畸形。研究确定了该菌株抗菌物质产生的最佳条件：培养温度300C；培养基初始pH值7．5；装液量为250ml三角瓶装液75ml培养基；培养时间120h。经30％～70％硫酸铵沉淀获得的抗茵粗提物对60℃处理具有稳定性（活性达97．8％）；对蛋白酶K具有部分耐受性，对胰蛋白酶和胃蛋白酶较敏感。

Preliminary study on antagonistic activity of antifungal substance from biocontrol bacterium Bacillus subtilis B29 was made by analyzing the inhibitory effect of cell-free supematant to mycelium growth and conidial spore germination of Fusarium oxysporum f. cucumerinum. The results showed that the antifungal substance secreted by the strain B29 inhibited the growth of Fusarium oxysporium f. cucumerinum and conidial spore germination. The optimum fermentation conditions of antifungal substance from strain B29 were original pH7.5, 75ml/250ml at 30℃ for 120h. The antifungal substance was precipitated by （NH4）2SO4 from 30% to 70%. The crude antifungal substance of strain B29 was stable to heat at some extent, partially tolerant to proteinase K, and more sensitive to trypsinase and pepsin.