Entomopathogenic fungi of the genus Cordyceps biotransform zearalenone - metabolomic and proteomic backgrounds

Zearalenone (ZEN) is a mycotoxin that poses risks to animals and humans. Its metabolism in humans is well understood, but its biotransformation by fungi that co-exist in soil with Fusarium is not yet elucidated. In this study, the ability of the commonly used biocontrol agent Cordyceps to eliminate ZEN was evaluated. Overall, 19 phase I and II derivatives of ZEN biotransformation by reduction, oxidation, sulfonation, glycosylation and glucuronidation were detected. Importantly, new metabolites of ZEN biotransformation by fungi were discovered. C. fumosorosea and C. farinosa bioconverted ZEN to its oxidized and sulfonated form. Additionally, C. fumosorosea biotransformed zearalenol, the reduced metabolite of ZEN, via oxidation and sulfonation. Mechanistically, cytochrome P450 of the Cordyceps spp. catalyzed the oxidation of ZEN and its metabolites. Sulfate adenylyltransferase and adenylyl-sulfate kinase were responsible for sulfonation in the ZEN biotransformation pathway in C. fumosorosea. Additionally, enzymes that may be involved in the glycosylation and reduction were determined by proteomic research. Moreover, ZEN was found to decrease the level of beauvericin in C. fumosorosea, which could lead to the reduction in environmental pollution with this compound.