解淀粉芽孢杆菌BI2抗真菌活性物质的分离纯化及特性分析

从秸秆饲料中分离得到一株解淀粉芽孢杆菌BI2,它对黄曲霉具有较强的拮抗作用。发酵液经过离心、膜过滤和离子交换法得到粗提物。粗提物对温度不敏感,100℃加热30min,活性损失25.8%;在弱酸性、中性及碱性条件下都具有较好的稳定性,并且对木瓜蛋白酶、胰蛋白酶和胃蛋白酶不敏感。粗提物经过中低压制备色谱得到单一化合物,经质谱分析测定分子量为436.2052u。采用微孔法测得该抗真菌物质的最小抑菌浓度为7.8μg/mL。 

Purification and characterization of antifungal substance from Bacillus amyloliquefaciens BI2

Bacillus amyloliquefaciens BI₂ isolated from straw feed was showed to be strongly antagonistic against Aspergillus flavus. Crude extract of antifungal substance was obtained by centrifugation, membrane filtration and ion exchange chromatography and it was stable at high temperature. The antifungal activity was not influenced disposing for 30min under 100℃, and only 25. 8% loss of activity was suffered. Antifungal substance, which could be steady at pH 6. 0 to pH 12. 0, was tested to have strong tolerant to several proteases, such as Trypsin, Pepsin and Papain. Finally the antifungal substance was isolated and purified by flash chromatography, and its molecular weight determined by mass spectrometry was 436. 2052u. Assay using 96-well plate illustrated that the minimum inhibitory concentration of the antifungal substance against Aspergillus flavus was 7. 8μg/mL.