A Novel Glycosyltransferase from Achieves Zearalenone Detoxification by Diglycosylation Modification

Zearalenone (ZEN), a nonsteroidal estrogenic mycotoxin produced by spp., contaminates cereals and threatens human and animal health by inducing hepatotoxicity, immunotoxicity, and genotoxicity. In this study, a new strain, YQ-1, with a strong ability to detoxify ZEN, was isolated from soil samples and characterized. YQ-1 was confirmed to degrade more than 46.26% of 20 μg mL ZEN in Luria-Bertani broth and 98.36% in fermentation broth within 16 h at 37 °C; one of the two resulting products was ZEN-diglucoside. Under optimal reaction conditions (50 °C and pH 5.0-9.0), the reaction mixture generated by YQ-1 catalyzing ZEN significantly reduced the promoting effect of ZEN on MCF-7 cell proliferation, effectively eliminating the estrogenic toxicity of ZEN. In addition, a new glycosyltransferase gene (yqgt) from YQ-1 was cloned with 98% similarity to Bs-YjiC from 168 and over-expressed in BL21 (DE3). ZEN glycosylation activity converted 25.63% of ZEN (20 μg mL) to ZEN-diG after 48 h of reaction at 37 °C. The characterization of ZEN degradation by YQ-1 and the expression of YQGT provide a theoretical basis for analyzing the mechanism by which spp. degrades ZEN.