纳豆芽孢杆菌发酵液抑菌物质的提取与初步分析

Extraction and Preliminary Analysis of Antibacterial Substance from Bacillus natto Fermentation

利用纳豆芽孢杆菌发酵大豆蛋白制备具有抑菌活性的发酵液,使用硫酸铵沉淀法对发酵液中的抑菌成分进行提取。研究温度、pH和蛋白酶对提取液抑菌性的影响,SDS-PAGE凝胶电泳测定提取液组成及分子量,Sephadex G-75对组分进行分离并对其进行抑菌验证。结果表明:温度升高提取液抑菌活性有所下降,在超过100℃时几乎失去抑菌活性;提取物在pH 5-9时变化不敏感,在pH 3和pH 11时略有影响;经蛋白酶处理后提取液抑菌性明显降低,蛋白酶添加量255U/mL时几乎无抑菌性;提取液经SDS-PAGE电泳分离出相对分子质量6.6×104和3.0×104两个组分,经葡聚糖离子交换柱层析分离出两个组分,经验证3.0×104分子量的组分具有抑菌性。

Bacillus natto fermented soybean protein to prepare fermentation liquor with antibacterial activity. Extract the antibacterial substance with ammonium sulfate. Research the effect of temperature, pH and protease on the extraction. Measure the molecular weight with SDS-PAGE and there were two components with molecular weight of 6.6×10^4 and 3.0×10^4, the Sephadex G-75 separated the effective components. The result indicates that the antibacterial activity decreased with temperature higher and it lost the activity above 100℃. The extraction wasn＇t sensitive to pH and it had effect with pH 3 and pH 11. The activity decreased with protease addition increased and it lost the activity when the addition was 255U/mL. SDS-PEGE and Sephadex G-75 extracted two constituents of 3.0×10^4 and 6.6×10^4 molecular weight and it proved that the lighter weight constituent showed antibacterial activity.