Enzymatic Degradation of Multiple Major Mycotoxins by Dye-Decolorizing Peroxidase from Bacillus subtilis

Abstract

The co-occurrence of multiple mycotoxins, including aflatoxin B₁ (AFB₁), zearalenone (ZEN) and deoxynivalenol (DON), widely exists in cereal-based animal feed and food. At present, most reported mycotoxins degrading enzymes target only a certain type of mycotoxins. Therefore, it is of great significance for mining enzymes involved in the simultaneous degradation of different types of mycotoxins. In this study, a dye-decolorizing peroxidase-encoding gene <i>BsDyP</i> from <i>Bacillus subtilis</i> SCK6 was cloned and expressed in <i>Escherichia coli</i> BL21/pG-Tf2. The purified recombinant <i>Bs</i>DyP was capable of oxidizing various substrates, including lignin phenolic model compounds 2,6-dimethylphenol and guaiacol, the substrate 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), anthraquinone dye reactive blue 19 and azo dye reactive black 5, as well as Mn²⁺. In addition, <i>Bs</i>DyP could efficiently degrade different types of mycotoxins, including AFB₁, ZEN and DON, in presence of Mn²⁺. More important, the toxicities of their corresponding enzymatic degradation products AFB₁-diol, 15-OH-ZEN and C₁₅H₁₈O₈ were significantly lower than AFB₁, ZEN and DON. In summary, these results proved that <i>Bs</i>DyP was a promising candidate for the simultaneous degradation of multiple mycotoxins in animal feed and food.