黄曲霉毒素B1高效降解菌株的筛选鉴定及其降解

以香豆素为唯一碳源,利用微生物去毒法,初步筛选出32株生长良好的活性菌株,再添加AFB1标准品(菌液毒素终质量浓度2.5μg/m L),通过高效液相色谱(HPLC)检测AFB1降解率,结果显示,从鸡粪中分离并命名为F6的菌株高效降解黄曲霉毒素B1,降解率达83%。对菌株F6进行细胞形态及生理生化特性鉴定,初步判断为芽胞杆菌属,16S rRNA序列同源性比对分析,与蔬菜芽胞杆菌国际标准株ATCC700005(登录号NR043325.1)核苷酸同源性为99.3%,由此可确定,F6菌株为蔬菜芽胞杆菌,命名为Bacillus oleronius GX01(登录号KP297896)。分离菌株F6发酵液各组分,检测得上清液AFB1降解率达83%,而菌悬液、胞内液的AFB1分别仅为22.8%、17.4%,初步鉴定其降解活性成分可能为胞外酶。

Isolation,identification and preliminary degradation of aflatoxin B1 degrading bacterial strain

To select strains capable of degrading aflatoxin B1 (AFB1)efficiently,32 bacteria strains were isolated from different sources which display AFB1 reduction activity,using coumarin as the sole carbon source and biodegradation technology.AFB1 degradation effectiveness was detected by high-per-formance liquid chromatography (HPLC)after AFB1 standard was added (final concentration of culture supernatant was 2.5 μg/mL).The bacteria strain isolated from chicken manure was named as F6, which could degrade AFB1 by 83.3%.Based on the morphologic,physiological,biochemical character-istics,the isolated strain F6 was preliminary identified as Bacillus .The analysis of 1 6S rRNA gene se-quence homology revealed that,the nucleotide identity between strain F6 and Bacillus oleronius interna-tional standard strain ATCC700005 (accession number NR043325.1)was 99.3%.Thus,strain F6 was determined as B .oleronius and named as B .oleronius GX01 (Accession No.KP297896).The compo-nents of the fermentation broth of F6 were then isolated and detected.The results showed that the cul-ture supernatant could degrade 83% AFB1,while the degradation rates of bacterial suspension and in-tracellular were 22.8% and 17.4%,respectively,suggesting that the degradation activity of B .olero-nius strain F6 was exoenzyme.