Three recombinant peroxidases as a degradation agent of aflatoxin M1 applied in milk and beer

The aim of this work was to estimate the effects of three recombinant peroxidases (rPODs) on the degradation of aflatoxin M1 (AFM1) in a model solution and were applied in milk and beer to study the AFM1 degradation. Besides, the contents of AFM1 in model solution, milk and beer were evaluated, and the kinetic parameters of rPODs were determined (Michaelis-Menten constant - Km and maximal velocity - Vmax). The optimized reaction conditions (The degradation was over 60 %) for these three rPODs in the model solution were, respectively as follows: pH were 9, 9, and 10; hydrogen peroxide concentrations were 60, 50, and 60 mmol/L; at an ionic strength of 75 mmol/L and reaction temperature of 30 degrees C with 1 mmol/L K+ or 1 mmol/L Na+. These three rPODs (1 U /mL) presented the maximum activity for degradation of AFM1 of 22.4 %, 25.6 %, and 24.3 % in milk, while 14.5 %, 16.9 %, and 18.2 % in beer, respectively. Meanwhile, the survival rate of Hep-G2 cells raised about 1.4 times after treated with peroxidase-generated AFM1 degradation products. Therefore, POD may be a promising alternative to reduce the pollution of AFM1 in model solution, milk, beer, and minimize their impact on the environment in humans.