Three recombinant peroxidases as a degradation agent of aflatoxin M 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 M (AFM) in a model solution and were applied in milk and beer to study the AFM degradation. Besides, the contents of AFM in model solution, milk and beer were evaluated, and the kinetic parameters of rPODs were determined (Michaelis-Menten constant - K and maximal velocity - V). 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 °C with 1 mmol/L K or 1 mmol/L Na. These three rPODs (1 U /mL) presented the maximum activity for degradation of AFM 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 AFM degradation products. Therefore, POD may be a promising alternative to reduce the pollution of AFM in model solution, milk, beer, and minimize their impact on the environment in humans.