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枯草芽孢杆菌B26发酵液离心过微孔滤膜后,用质量分数为70%的硫酸铵沉淀,透析后获得仍具有拮抗多隔镰孢霉的无菌粗提物。进一步检测了粗提物对温度、酸碱度、紫外线照射、有机溶剂和蛋白酶处理的稳定性。结果表明,B26粗提物对高温具有一定的耐受性,经100℃处理后,是常温处理下抑菌直径的78.2%,但经121℃处理后,B26粗提物完全失去活性。B26粗提物具有较宽的pH值适应范围,在pH值3～10时都具有抑菌活性,且在pH值为7时的抑菌能力最高。粗提物对紫外线照射有部分敏感性,经距离40cm、功率20W的紫外灯照射80min后,抑菌活性是对照的78.1%。有机溶剂对B26抑菌粗提物的活性影响很小,经乙醚,甲醇,氯仿和丙酮处理30min后,粗提物抑菌活性分别为对照的96.4%,85.7%,82.1%,81.5%。B26抑菌粗提物对蛋白酶具有部分敏感性,蛋白酶K、胰蛋白酶和胃蛋白酶处理后的拮抗直径分别为15.2,16.2,16.3mm,抑制率分别是对照的76.7%,81.8%和83.3%。
The Bacillus subtilis B26 fermentation broth was centrifuged through a microporous membrane filter and precipitated with 70% ammonium sulfate, followed by dialysis to obtain a sterile crude extract still resistant to Fusarium seile. The crude extracts were further tested for stability against temperature, pH, UV irradiation, organic solvents and protease treatment. The results showed that the crude extract of B26 had a certain tolerance to high temperature. After 100 ℃ treatment, it was 78.2% of the bacteriostatic diameter under normal temperature. However, after the treatment at 121 ℃, the crude extract of B26 completely lost its activity. B26 crude extract has a wide range of pH to adapt to the pH 3-10 have antibacterial activity, and at pH 7, the highest antibacterial capacity. The crude extract was partially sensitive to ultraviolet radiation. After 80cm UV irradiation at a power of 20W for 80min, the antibacterial activity was 78.1% of the control. The organic solvent had little effect on the activity of B26 antimicrobial crude extracts. The antibacterial activity of the crude extract was 96.4%, 85.7%, 82.1% and 81.5% of the control after treated with diethyl ether, methanol, chloroform and acetone for 30min. The antibacterial crude extract of B26 was partially sensitive to protease. The antagonistic diameters of protease K, trypsin and pepsin were 15.2, 16.2 and 16.3 mm, respectively. The inhibition rate was 76.7%, 81.8% and 83.3% respectively.