溶解性有机质对电化学-微生物耦合降解17α-乙炔基雌二醇的介导机制

Electrochemical and microbial degradation become the main techniques to remove endocrine disrupting chemicals. Dissolved organic matter (DOM) not only used as redox mediators for promoting 17α-ethynylestradiol (EE2) microbial degradation, but also can be stimulated by electrically charged anode to produce active substances for EE2 decomposition or mineralization in the electrochemical reaction system. Therefore, DOM could play a very important role in mediating EE2 degradation by electrochemical-microbial coupling technology, but this process has not been studied. This project aims to build the coupling system of electrochemical and microbial degradation for EE2 with DOM addition, and the screened microorganisms in our previous study which can effectively degrade EE2, Ti/SnO2-Sb2O5 anode as well as graphite cathode are also applied in the system. The effects of electric field on the cell growth and metabolism, as well as community structure of microorganisms, and the mechanisms of activity substances produced by electro-stimulated DOM to degrade EE2, and mechanism of DOM mediating EE2 degradation by electrochemical-microbial coupling technology are investigated. And eco-toxicity and estrogenic activity for the EE2 degradation products are also evaluated. Thus, the project could enhance the understanding of DOM and provide the theoretical basis for using the coupling system to restore the estrogen-containing wastewater in future.

电化学降解和微生物降解是环境内分泌干扰物的主要处理技术。溶解性有机质（DOM）既可以在微生物体系中作为电子穿梭体（氧化还原介质）通过偶联微生物生长加速降解17α-乙炔基雌二醇（EE2）；又可以在电化学体系中被阳极激发产生活性物质提高EE2的降解或矿化效率。因此，在电化学-微生物耦合降解EE2的系统中，DOM将起到非常重要的介导作用，而此过程尚待研究。本项目拟利用前期研究筛选出的能有效降解EE2的微生物菌种，以Ti/SnO2-Sb2O5阳极、石墨板阴极，构建DOM参与的电化学-微生物耦合降解EE2体系。考察电场与微生物生长代谢和种群结构变化之间的相互影响、电激发DOM产生活性物质对EE2降解的作用机制，探究DOM对电化学-微生物体系耦合降解EE2的介导机制，并评价EE2降解产物的生态毒性和雌激素活性。研究成果将进一步加深对DOM的认识，并为后期利用该系统处理含类固醇雌激素废水提供理论基础。

类固醇雌激素（SEs）所造成的环境污染与健康问题已经成为全球关注的新的研究领域。研究表明溶解性有机质（DOM）不仅可以在微生物体系中作为电子穿梭体通过偶联微生物生长加速降解SEs，而且可以在电化学体系中被激发产生活性物质以提高EE2的降解或矿化效率。基于此，本研究先筛选出了有效降解EE2的微生物菌种，并以Ti/SnO2-Sn2O5为阳极、碳材料为阴极，构建了DOM参与的电化学-微生物耦合降解EE2体系。考察了电场与微生物生长代谢和种群结构变化之间的相互影响、电激发DOM产生活性物质对EE2降解的作用机制，探究了DOM对电化学-微生物体系耦合降解EE2的介导机制，并评估了EE2降解产物的生态毒性，论证了电化学联合微生物技术处理含EE2废水的可行性。结果显示，厌氧降解菌与电化学过程的耦合可以提高EE2的降解效率，降低微生物的多样性；富里酸（FA）和腐殖酸（HA）的存在明显提高了EE2的降解和矿化效率；电化学过程可以增加DOM中醌基的含量，进一步提高了DOM在微生物过程和光化学过程中的介导作用；EE2废水经电化学-微生物系统处理后其毒性明显降低。本项目的实施可以为雌激素污染废水的净化提供了新思路，为电化学-微生物技术在废水中去除类固醇雌激素的应用提供了理论依据。