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AFB1与ZEN的菌株,从全国多个省份的土壤、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-质谱联用技术分析显示,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,对AFB1与ZEN的脱毒率分别达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: The aim of this study was to screen strains capable of simultaneously degrading AFB1 and ZEN from soil samples, fermented food, animal manure, as well as moldy peanuts and corn collected from multiple provinces across the country. The results showed that the strain Bacillus amyloliquefaciens HNGD-Yq12 isolated from Chongqing maize-field soil exhibited degradation capabilities for both AFB1 and ZEN in its cell-free culture supernatant at 40 °C under neutral pH conditions, with degradation rates of 91.1% and 94.6%, respectively. The temperature-optimization experiments demonstrated that 40 °C was the optimal temperature for the degradation enzyme of this strain. When the temperature deviates from this range, the degradation efficiency is reduced, and, in particular, at temperatures below 30 °C the enzyme activity is markedly diminished, a pattern consistent with the typical activity-temperature characteristics of most microbial enzymes. Mn2+ significantly promoted the degradation of both AFB1 and ZEN, whereas Cu2+ specifically enhanced the degradation of AFB1. The metal-ion influence experiments suggested that different metal ions exert distinct regulatory effects on the degradation process. Notably, Mn2+ may serve as a cofactor or activator for certain degradation enzymes, whereas the specific promotion of AFB1 degradation by Cu2+ suggests that the degradation pathways of the two toxins may involve distinct enzymatic systems. Furthermore, based on analysis using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), AFB1 was transformed into C16H14O5 and C14H12O4, whereas ZEN was converted into 13-OH-ZEN-quinone (C18H20O6) . It is speculated that the toxic structures of these mycotoxins have been disrupted. Mass-spectrometric fragment analysis further revealed that the furan ring and coumarin moiety of AFB1 may undergo ring-opening reactions, while the lactone ring of ZEN was opened and subsequently oxidized; these structural alterations are identified as the key modifications responsible for the reduction in toxicity. In practical applications, treating peanut powder and corn powder with this strain achieved detoxification rates of 72.18% and 67.29% for AFB1 and ZEN, respectively. In conclusion, Bacillus amyloliquefaciens HNGD-Yq12 exhibits excellent application potential in the simultaneous degradation of multiple mycotoxins. Future research will focus on the isolation, purification, and identification of degradation-active components, the cloning and heterologous expression of degradation gene clusters, and the development of enzyme preparation processes applicable to large-scale production to facilitate the translation of this technology from laboratory research to practical application.

       

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