College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, National-Local Joint Engineering Laboratory of Intelligent Food Technology and Equipment, Zhejiang University, Hangzhou 310058, Zhejiang, China.
J Appl Microbiol. 2023 Sep 5;134(9). doi: 10.1093/jambio/lxad192.
This study aimed to screen a bacterial strain with high detoxifying capability for aflatoxin B1 (AFB1), verify its biotransformation efficiency, and detoxification process.
A total of 350 samples collected from different environmental niche were screened using coumarin as the sole carbon source. High Performance Liquid Chromatography (HPLC) was used to detect residues of AFB1, and 16S rRNA sequencing was performed on the isolated strain with the highest AFB1 removal ratio for identification. The detoxified products of this strain were tested for toxicity in Escherichia coli as well as LO2, Caco-2, and HaCaT human cell lines. HPLC-MS was applied to further confirm the AFB1 removal and detoxification process.
We identified a strain from plant leaf designated as DT with high AFB1-detoxifying ability that is highly homologous to Bacillus aryabhattai. The optimum detoxification conditions of this strain were 37°C and pH 8.0, resulting in 82.92% removal ratio of 2 μg mL-1 AFB1 in 72 h. The detoxified products were nontoxic for E. coli and significantly less toxic for the LO2, Caco-2, and HaCaT human cell lines. HPLC-MS analysis also confirmed the significant drop of the AFB1 characteristic peak. Two possible metabolic products, C19H15O8 (m/z 371) and C19H19O8 (m/z 375), were observed by mass spectrometry. Potential biotransformation pathway was based on the cleavage of double bond in the terminal furan of AFB1. These generated components had different chemical structures with AFB1, manifesting that the attenuation of AFB1 toxicity would be attributed to the destruction of lactone structure of AFB1 during the conversion process.
本研究旨在筛选具有高效脱毒黄曲霉毒素 B1（AFB1）能力的细菌菌株，验证其生物转化效率和脱毒过程。
采用香豆素作为唯一碳源，从不同环境生态位中筛选了 350 个样本。采用高效液相色谱法（HPLC）检测 AFB1 的残留量，对去除率最高的分离菌株进行 16S rRNA 测序鉴定。对该菌株的脱毒产物进行毒性测试，包括大肠杆菌以及 LO2、Caco-2 和 HaCaT 人细胞系。采用 HPLC-MS 进一步确认 AFB1 的去除和脱毒过程。
我们从植物叶片中鉴定出一株具有高效 AFB1 脱毒能力的菌株，命名为 DT，该菌株与 Bacillus aryabhattai 高度同源。该菌株的最佳脱毒条件为 37°C 和 pH 8.0，在 72 小时内可将 2μg mL-1 AFB1 的去除率提高到 82.92%。脱毒产物对大肠杆菌无毒，对 LO2、Caco-2 和 HaCaT 人细胞系的毒性明显降低。HPLC-MS 分析也证实了 AFB1 特征峰的显著下降。通过质谱观察到两个可能的代谢产物，C19H15O8（m/z 371）和 C19H19O8（m/z 375）。潜在的生物转化途径是基于 AFB1 末端呋喃双键的断裂。这些生成的成分与 AFB1 具有不同的化学结构，表明 AFB1 毒性的减弱归因于转化过程中 AFB1 内酯结构的破坏。
