Effect and Mechanism of Armillaria mellea 07-22 Fermentation on the Degradation of Zearalenone

This study used Armillaria mellea 07-22 as the experimental strain to degrade zearalenone (ZEN) by fungal biological fermentation. The degradation effects of Armillaria mellea on ZEN were studied, including the degradation effects of different concentrations of ZEN by the strain and the effects of different culture time, culture temperature, initial pH value and inoculation amount on the degradation of ZEN by the strain. Then the degradation mechanism was explored, the degradation effects of mycelium, fermentation supernatant and cell contents on ZEN were analyzed, and the effects of different fermentation time, pH values, and metal ions on degradation of ZEN by fermentation supernatant were studied, and the correlation between degradation effect and laccase production activity of the strain was illustrated. The results showed that Armillaria mellea 07-22 had a good degradation effect on ZEN. When the ZEN concentration was 5 μg/mL, the optimal degradation conditions were culture time of 8 days, culture temperature of 27 ℃, initial pH of 7.0, and inoculation amount of 10%. At this time, the degradation rate of ZEN was 78.72%. The degradation rates of ZEN by mycelium, fermentation supernatant and cell contents were 47.42%, 37.05% and 13.08% respectively. The extracellular enzymes secreted by Am-07-22 were the main way to degrade ZEN, and the mycelium cells also had a certain adsorption effect on ZEN. In addition, the correlation between the degradation rate of ZEN by fermentation supernatant and laccase activity was 0.973, and Cu2+ had the best promoting effect on the degradation of ZEN by fermentation supernatant.