Process optimization and molecular docking analysis of laccase degradation of aflatoxin B1 in peanut cake
In order to promote the practical application of laccase in the removal of aflatoxin B1(AFB,)in peanut cake/meal,moldy peanut cake was used as the experimental object to degrade AFB,by laccase.The effects of enzyme dosage,system pH,reaction temperature,reaction time and solid-liquid ratio on the degradation rate of AFB1 were investigated,and the process conditions for the degradation of AFB,in peanut cake by laccase were optimized.The interaction model between laccase and AFB,was analyzed by molecular docking.The results showed that the optimal conditions for the degradation of AFB,in peanut cake by laccase were obtained as follows:enzyme dosage 5 U/g,system pH 6.0,reaction time 48 h,reaction temperature 45 ℃ and solid-liquid ratio 1∶10.Under these conditions,the degradation rate of AFB,in peanut cake was as high as 83.5％,and the residual amount of AFB,was 15.8 μg/kg,which met the requirements of national standard(≤50 μg/kg).Molecular docking results showed that a hydrogen bond network was formed between AFB,and the amino acid residues His109,Ser110,His111,Ser113,His452 and Asp456 in the active cavity of laccase.The mechanism of degradation of AFB1 by laccase might be related to the hydrogen bond network.In summary,laccase has high degradability to AFB1,which has great application prospect in detoxification treatment of moldy peanut cake.
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