New application of a dye-decolorizing peroxidase immobilized on magnetic nanoparticles for efficient simultaneous degradation of two mycotoxins.

Nowadays the enzymatic approaches are the most promising strategies for mycotoxins detoxification in food stuffs. Herein, the dye-decolorizing peroxidase RhDypB from Rhodococcus jostii was studied for its ability to degrade two mycotoxins in both free and the immobilized enzyme forms. This enzyme was recombinantly expressed and purified, while FeO nanoparticles were prepared and modified with chitosan as the immobilization carrier. The immobilized enzyme FeO@CS@RhDypB demonstrated degradation rate of 85.61 % toward aflatoxin B, while it was firstly found to be able to degrade zearalenone with the rate of 86.52 %, at pH 4.0 on 30 °C. The degradation products were identified as aflatoxin Q and 15-OH-ZEN respectively. After 5 cycles of reuse, FeO@CS@RhDypB still exhibited degradation rates of 38.50 % and 49.76 % toward the mycotoxins, indicating its high reusability. Moreover, FeO@CS@RhDypB exhibited excellent stability after 10 days of storage. This work identified potential applications of nanoparticle-immobilized enzyme for biodegradation of mycotoxins in food industry.