降解黄曲霉毒素B_1菌株的筛选及毒素降解酶的分离

Screening of Aflatoxin B_1 Degradation Strains and Purification of AFB_1-degrading Enzyme

为了筛选具有降解黄曲霉毒素B_1(AFB_1)作用的菌株,并分离纯化高效AFB_1降解酶,以AFB_1作为降解AFB_1菌株生长的能源和碳源进行初筛,将初筛得到的菌株接种于含有AFB_1的培养基中,选择降解率最高的菌株进行固体发酵培养后提取粗酶液,通过硫酸铵分级沉淀和葡聚糖凝胶对降解AFB_1的活性物质进行分离,SDS-PAGE蛋白质电泳检测降解酶蛋白质分子质量大小,并通过酶联免疫法测定不同分子质量的酶蛋白对AFB_1的降解率,26S rDNA和同源序列分析对降解率最高的菌株进行菌种鉴定。结果显示,降解AFB_1能力最高的菌株为Y8,降解率为77.05%,凝胶层析分离出的31.7 ku的酶蛋白对AFB_1的降解率达54.33%;菌种鉴定结果表明,真菌Y8为米曲霉。综上,筛选的米曲霉Y8能够高效降解AFB_1,可有效缓解黄曲霉毒素对畜禽的危害,具有提高养殖效益的潜在应用价值。

The aim of this experiment was mainly to screen the strains degraded aflatoxin B 1(AFB 1)and to purify AFB 1-degrading enzyme.The AFB 1 was used as the carbon source and energy for the primary screening strains culture,and the strains which could degrade aflatoxin B 1 were isolated.The AFB 1-degrading enzyme was purified by ammonium sulfate precipitation and Sephadex from solid fermenting culture,and then the molecular mass of it and its AFB 1-degrading rate were measured by SDS-PAGE and ELISA,respectively.The strain with the highest AFB 1 degradation rate was identified by 26S rDNA and homologous sequence analysis.The results indicated that the strain Y8 possessed the highest AFB 1 degradation rate(77.05%),however,the AFB 1-degrading enzyme isolated from Y8,which the molecular mass was 31.7 ku,had a AFB 1-degrading rate of 54.33%.The Y8 was identified as Aspergillus oryzae can efficiently degradate the AFB 1 and there is a potential application in livestock and poultry raising.