黄曲霉毒素B1降解菌的筛选鉴定

    Screening and Identification of Aflatoxin B1 Degradation Strains

    • 摘要: 黄曲霉毒素的化学结构与香豆素十分类似,具有极强的毒性、致癌性,被认为是饲料和食品中不可避免的污染物。对黄曲霉毒素污染的控制亟须一种安全、高效、环保的脱毒方法。以香豆素作为唯一碳源的培养基筛选黄曲霉毒素B1降解菌,最终筛选出1株对AFB1降解率可达到91.86%的菌株(HH-1),对其进行了16S rDNA基因序列测定,系统发育进化法显示其为地衣芽孢杆菌。将地衣芽孢杆菌发酵液分为上清液和菌悬液,验证各组分对黄曲霉毒素的降解效率。结果表明:地衣芽孢杆菌的上清液降解活性最高,确定有效活性成分存在于上清液中;对上清液进行高温和蛋白酶K变性处理后,降解活性显著降低,初步判定降解黄曲霉毒素B1的有效活性成分是一种胞外酶。进一步利用高效液色谱对黄曲霉毒素B1的降解产物进行了研究,并检测到降解产物P1和P2

       

      Abstract: The chemical structure of aflatoxins (AFs) is very similar to coumarin.It has strong toxicity,carcinogenicity,and is an unavoidable pollutant in feed and foods.It is urgent to develop effective and environmentally friendly detoxification methods for degrading aflatoxins.In order to isolate bacteria with AFs degradation activity,screening was carried out using coumarin,a structural analogue of AFs,as the sole carbon source.As a result,one strain (HH-1) with high degradation rate (91.86%) was obtained.16S rDNA gene sequencing confirmed it as a strain of Bacillus licheniformis.Broth culture of HH-1 were divided into different components including culture supernatant and bacterial cell.The results indicated that the activity of aflatoxins degradation mainly existed in the culture supernatant of strain HH-1 rather than in bacterial cells.High temperature and protease K treatments suggested that its degradation activity was largely due to the action of extracellular enzymes.The degradation products P1 and P2 of AFs were also detected by high performance liquid chromatography.

       

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