改性蒙脱石固定化漆酶脱除剂的制备及脱除黄曲霉毒素B1研究

    Preparation of the immobilized laccase remover with modified montmorillonite for the removal of aflatoxin B1

    • 摘要: 为了提升脱除剂的吸附水平和可重复利用能力,并用于脱除黄曲霉毒素B1(AFB1),利用十六烷基三甲基溴化铵(CTAB)改性处理蒙脱石(MMT-CTAB),结合固定化漆酶(Laccase)制得改性蒙脱石固定化漆酶(MMT-CTAB-Lac),利用方程拟合考察脱除剂的吸附动力学,优化MMT-CTAB-Lac脱除AFB1最适条件,并利用LC-MS和T.E.S.T软件探究AFB1降解途径及其降解产物毒性。改性处理后的脱除剂具有更大层间距和孔容、更小颗粒粒径,吸附AFB1的比表面积增大;吸附于脱除剂中的AFB1被固定化漆酶降解,有效阻止了AFB1在脱除剂上的聚集,显著增大了MMT-CTAB-Lac吸附容量;化学吸附是AFB1吸附过程中限速步骤,MMT-CTAB-Lac对AFB1的吸附量为44.5 mg·g-1,高于MMT-CTAB的吸附量;MMT-CTAB-Lac对AFB1脱除率为67%,且在弱酸及中性条件下均具有良好催化降解效果。进一步鉴定了MMT-CTAB-Lac降解AFB1的产物,并提出了其降解AFB1的两种可能途径:第1种可能降解途径(内酯环结构被破坏),降解产物为C17H14O7和C16H12O5;第2种可能降解途径(呋喃环结构被破坏),降解产物为C17H14O7、C16H12O7和C14H10O4。并通过T.E.S.T软件的毒性预测,得出降解产物毒性有所降低。本研究开发的MMT-CTAB-Lac为粮油食品中AFB1的安全、高效脱除奠定了重要基础。

       

      Abstract: 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 ammonium 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 particle size, and the increased specific surface area for the AFB1 adsorption. The AFB1 adsorbed on the remover was degraded by the immobilized laccase, which effectively prevented the accumulation of AFB1 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 AFB1 was 44.5 mg·g-1, which was higher than that of MMT-CTAB. The removal rate of AFB1 by the MMT-CTAB-Lac was 67%, with the high catalytic degradation rate under the weak acid and neutral condition. The degradation of AFB1 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 (destruction 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 AFB1 in the field of grain, oil and food.

       

    /

    返回文章
    返回