Preparation of the immobilized laccase remover with modified montmorillonite for the removal of aflatoxin B1
In this study,the removal agent of modified montmorillonite immobilized laccase(MMT-CTAB-Lac)was prepared for the removal of Aflatoxin B1(AFB1).After the treatment of cetyltrimethyl ammoni-um bromide(CTAB),the MMT-CTAB-Lac was prepared by the modified montmorillonite(MMT-CTAB)with the immobilized laccase.The adsorption kinetics of the removal agent was investigated by the equation fitting.The conditions for removing AFB1 from the MMT-CTAB-Lac were optimized.The AFB1 degradation pathway and the toxicity of its degradation products were investigated by the LC-MS and T.E.S.T software.After the modification,the remover had larger layer spacing and pore volume,smaller parti-cle size,and the increased specific surface area for the AFB,adsorption.The AFB,adsorbed on the remov-er was degraded by the immobilized laccase,which effectively prevented the accumulation of AFB,on the remover,and significantly increased the adsorption capacity of MMT-CTAB-Lac.The chemisorption was a rate-limiting step in the adsorption process of AFB1.The adsorption capacity of MMT-CTAB-Lac for AFB,was 44.5 mg·g-1,which was higher than that of MMT-CTAB.The removal rate of AFB,by the MMT-CTAB-Lac was 67％,with the high catalytic degradation rate under the weak acid and neutral con-dition.The degradation of AFB,by MMT-CTAB-Lac was further identified.The two possible degradation pathways were proposed:the first possible degradation pathway(destruction of lactone ring structure),with the degradation products of C17H14O7 and C16H12O5;the second possible degradation pathway(de-struction of furan ring structure),with the degradation products of C17H14O7,C16H12O7,and C14H10O4.Through the toxicity prediction of T.E.S.T software,the toxicities of degradation products were reduced.The MMT-CTAB-Lac developed in this study lays an important foundation for the safe and efficient removal of AFB,in the field of grain,oil and food.
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