Combined in silico investigation and in vitro characterization of the zearalenone detoxification potential of dye-decolorizing peroxidase from Bacillus subtilis 168

Zearalenone (ZEN), one of the most hazardous mycotoxins commonly present in food, causes severe safety risks to human health. In this work, the ZEN detoxification potential of dye-decolorizing peroxidase BsDyP from Bacillus subtilis 168 was investigated by a combined computational and experimental study. Molecular docking and dynamics simulation suggested that BsDyP could allow the binding of ZEN at the gamma-edge of heme and surface exposed redox-active Tyr335 residue. Consistently, the recombinant BsDyP expressed in Escherichia coli was found to be capable of directly oxidizing 83% of ZEN with H2O2 as an electron acceptor. Moreover, the presence of 2, 2 '-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) as a redox mediator of BsDyP could enhance ZEN degradation to more than 98% in the pH range of 5.0-10.0. BsDyP-catalyzed ZEN degradation could be regarded as detoxification as the transformation product displayed much less estrogenicity. Moreover, bi-enzymes system including glucose oxidase (GOD) and BsDyP was applied to degrade ZEN in contaminated corn steep liquor and achieved a 33% degradation percentage. The findings suggested that BsDyP could be developed as a biocatalyst for detoxification of ZEN in contaminated food and feed.