解淀粉芽孢杆菌HNGD-Yq12对黄曲霉毒素B1和玉米赤霉烯酮的降解研究

    Degradation of aflatoxin B1 and zearalenone by Bacillus amyloliquefaciens HNGD-Yq12

    • 摘要: 为筛选可同步降解黄曲霉毒素B1(AFB1)与玉米赤霉烯酮(ZEN)的菌株,从全国多个省市自治区的土壤、发酵食品、动物粪便及霉变花生和玉米样本中分离并初步鉴定了若干菌株。结果表明,从重庆玉米地土壤中分离获得的解淀粉芽孢杆菌HNGD-Yq12,其无细胞培养上清液在40 ℃、中性条件下对AFB1与ZEN的降解率分别达91.1%与94.6%;Mn2+显著促进两种毒素的降解,而Cu2+特异性增强AFB1的降解;超高效液相色谱-串联质谱(UPLC-MS/MS)分析显示,AFB1转化为C16H14O5和C14H12O4,ZEN转化为13-OH-ZEN-quinone (C18H20O6),表明两种毒素的毒性结构均被破坏。在实际应用中,该菌株处理花生粉和玉米粉后,花生粉中AFB1与玉米粉中ZEN的降解率分别达72.18%和67.29%。综上,解淀粉芽孢杆菌HNGD-Yq12在同步降解多种真菌毒素方面展现出良好的应用潜力。

       

      Abstract: This study aimed to screen bacterial strains capable of simultaneously degrading aflatoxin B1 (AFB1) and zearalenone (ZEN) from soil samples, fermented foods, animal manure, as well as moldy peanuts and corn collected from multiple provinces of China. The results showed that Bacillus amyloliquefaciens HNGD-Yq12, isolated from maize-field soil in Chongqing, exhibited dual degradation capacity against AFB1 and ZEN. Its cell-free culture supernatant achieved degradation rates of 91.1% for AFB1 and 94.6% for ZEN under neutral pH conditions at 40 ℃. Temperature-optimization experiments confirmed 40 ℃ as the optimal temperature for the strain’s degradation enzymes. Deviation from this temperature significantly reduced the degradation efficiency. In particular, enzyme activity decreased markedly below 30 ℃, which is consistent with the typical temperature-dependent activity characteristics of most microbial enzymes. Mn2+ significantly promoted the degradation of both AFB1 and ZEN, whereas Cu2+ specifically enhanced the degradation of AFB1. Different metal ions exerted distinct regulatory effects on the mycotoxin degradation process. Notably, Mn2+ may act as a cofactor or activator for the degradation enzymes, whereas the specific promotion of AFB1 degradation by Cu2+ implies that AFB1 and ZEN may be degraded via different enzymatic pathways. Furthermore, ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis revealed that AFB1 was transformed into C16H14O5 and C14H12O4, whereas ZEN was converted into 13-OH-ZEN-quinone (C18H20O6). These transformations indicated structural disruption of the toxic moieties of the two mycotoxins. Further mass-spectrometric fragment analysis demonstrated that the furan ring and coumarin structure of AFB1 underwent ring-opening reactions, and the lactone ring of ZEN was cleaved and oxidized. Such structural modifications are responsible for the reduced toxicity of the degraded products. In practical detoxification applications, the strain treatment achieved detoxification rates of 72.18% for AFB1 and 67.29% for ZEN in artificially contaminated peanut powder and corn powder, respectively. In conclusion, Bacillus amyloliquefaciens HNGD-Yq12 possesses excellent potential for the simultaneous biodegradation of multiple mycotoxins. Future studies will focus on the isolation, purification, and identification of active degradation components, the cloning and heterologous expression of functional degradation gene clusters, and the development of scalable enzyme preparation processes, to promote the industrial translation and practical application of this detoxification technology.

       

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