电纺纳米纤维膜固定化酶及其催化转化典型PPCPs的反应机制

Electrospun nanofibrous membranes (ENMs) have been demonstrated to be excellent carriers for enzyme immobilization since they have a greater chance to overcome the difficulties in "separation and recycle" compared with traditional nanoparticles. Since it is a novel approach to the environmental field, the influence of the physicochemical properties of electrospun carriers and their combination ways with enzymes on catalytic transformation of organic pollutants is still unclear, the research on catalytic transformation mechanisms of typical environmental pollutants is insufficient. The specific objectives of this research and its scope are as follows: (1) to develop the technology of enzyme immobilization on electrospun nanofibrous membranes, study the effect of materials, enzyme-carrying forms and immobilization methods on enzyme catalytic kinetics; (2) to separate and analyze the transformation products of typical pharmaceutical and personal care products, such as diclofenac acid and triclosan, by the immobilized laccase/horseradish, thus reveal the transformation mechanism of the pollutants; (3) to analyze the major impact factors of PPCPs transformation by the immobilized enzymes, establish the reaction kinetics models and summarize the catalytic transformation mechanism of PPCPs by ENMs immobilized enzymes. The expected research achievements will provide new ideas and theoretical evidences for the practical application of ENMs immobilized enzyme in the field of environmental protection.

与传统的纳米颗粒相比，静电纺丝纳米纤维膜有望克服"分离和回收"的难题，降低环境风险，是优良的固定化酶载体。纳米纤维膜固定化酶在环境领域的应用是一个崭新的研究方向。迄今电纺载体材料物理化学性质及其与酶的结合方式对催化转化有机污染物的影响机制尚不明确，对典型环境污染物的催化转化机理研究匮乏。本项目拟针对以上问题开展如下研究：（1）建立以电纺纳米纤维膜为载体的高效固定化酶制备技术，研究材料、载酶形式和酶固定化方法对酶催化动力学特性的影响；（2）以固定化漆酶/辣根过氧化物酶催化转化典型PPCPs-双氯芬酸和三氯生为例，分离和表征转化产物，揭示污染物转化机理；（3）分析固定化酶催化转化PPCPs的主要影响因素，建立反应动力学模型，阐明纳米纤维膜固定化酶催化转化PPCPs的机制。本项目的研究成果将为电纺纳米纤维膜固定化酶在环境领域的实际应用提供新思路和理论依据。

近年来，静电纺丝纳米纤维膜固定化酶应用于水体中污染物的治理是环境领域的新兴研究热点。本项目旨在探究纳米纤维膜固定化酶的高效制备技术，探究不同因素对固定化酶的酶学性质及催化效率的影响，并探究固定化酶在去除水中污染物的应用潜力，阐明固定化酶催化转化PPCPs的影响因素，建立固定化酶催化转化PPCPs的机制。研究结果表明，酶固定化方法的选择与固定化酶载体材料的选择息息相关。以包埋法和表面担载法固定化酶均提高了固定化酶的pH稳定性、热稳定性、储藏稳定性以及操作稳定性，拓宽了酶的最适pH和温度范围。其中包埋法载酶量较低，酶活保留较大，表面担载法载酶量大，对污染物的去除效率更高。向纳米纤维膜中掺杂不同的纳米颗粒，可以起到增大比表面积、提高拉伸强度、提高电子转移能力等不同作用。总的来说，纳米颗粒的掺杂可以提高纳米纤维膜固定化酶的稳定性，增大与污染物的接触面积，提高对污染物的去除效率。固定化酶对于水中PPCPs的去除分为两个方面，纳米纤维膜的吸附作用以及酶的催化作用。对污染物的去除受pH、温度、污染物浓度等不同因素的影响，不同PPCPs的最佳处理条件不同。本项目的研究成果将为电纺纳米纤维膜固定化酶在环境领域的实际应用提供新思路和理论依据。