析氢电位下电活性生物膜对甲砜霉素的降解效能与机理研究

Thiamphenicol is a widely used broad-spectrum antibacterial agent in animals and human body. It has been detected frequently in various environmental substrates, and been typical antibiotic pollution factors. The long-term existence of thiamphenicol is potentially harmful to human health and destructive to the balance of the ecosystem. However, the present studies for the biodegradation of thiamphenicol are relatively insufficient. Microbial electrochemical technologies (METs) are developed to degrade refractory pollutants efficiently in recent years, and METs are environmentally friendly. Moreover, it is more targeted and potential for organic halogenated pollutants by combining METs with hydrogen dehalogenation. The project intends to control the potential of hydrogen evolution to produce hydrogen by controlling METs, and construct the system of thiamphenicol degradation by electrochemically active biofilms (EABs) under the potential of hydrogen evolution. This project would discuss the thiamphenicol degradation efficiency, influencing factors, degradation products, electron transport pathways and micro-ecological environment changes etc. from the aspects of EABs, applied voltage assisted EABs and EABs under the potential of hydrogen evolution by carrying out a step-by-step method. This project is also conducted to explore the effects on the thiamphenicol degradation efficiency of different electrode materials by EABs under the potential of hydrogen evolution and explore the possible negative effects. This project would expound the degradation mechanisms of thiamphenicol by EABs under the potential of hydrogen evolution based on these studies. Above all, the project would provide technical support and theoretical basis for the degradation of thiamphenicol by the associated degradation methods of microbiology, electrochemistry, hydrogen reduction.

甲砜霉素是畜禽和人体常用的广谱抗生素，在多种环境介质内高频检出，为典型的抗生素污染因子。甲砜霉素长期暴露对人类健康具有潜在危害性，并破坏生态系统平衡，而目前对甲砜霉素的生物降解研究不足。微生物电化学技术（METs）是近年来发展的可高效降解难降解污染物的技术，具有环境友好性，将其与氢气脱卤结合对有机卤代污染物的降解更具有针对性和发展潜力。本项目拟通过控制微生物电化学系统析氢电位产氢，构建析氢耦合电活性生物膜（EABs）降解甲砜霉素体系，采用逐级深入的研究方法，研究METs两极EABs、外电压辅助EABs、析氢电位下EABs对甲砜霉素的降解效能、影响因素、降解产物、电子传递路径与微生态环境变化等；并探究不同电极材料对析氢电位下EABs降解甲砜霉素的影响及可能产生的负效应，阐明析氢电位下EABs对甲砜霉素的降解机理。为建立甲砜霉素的微生物学、电化学、氢气还原联合降解体系提供技术支撑和理论依据。

抗生素在多种环境介质内高频检出，为典型的新污染物。抗生素的长期暴露对人类健康具有潜在危害性，并对生态系统平衡具有破坏性。本项目利用电活性生物膜EABs对土霉素进行同步降解及产能研究，研究发现在共基质条件下，阳极和阴极EABs的降解主要发生在前2d，后出现缓慢趋势，阴极EABs对土霉素的去除率达95.0%，阳极EABs为 91.8%，均显著高于对照；阳极EABs中的优势菌种为沙门氏菌和特拉布斯氏菌分别为51.1%和31.94%，两者为重要抗菌性菌种，最典型的产电菌地杆菌在阳极占5.08%，提高胞外电子传递效率和提升电化学性；漠河菌和丛毛单胞菌分别在阴极EABs中占12.06%和4.48%，与好氧条件下的生物降解有关，剑菌、鞘氨醇单胞菌、亚硝化单胞菌等在阴极EABs中含量较高与土霉素的生物降解有关，假单孢菌、固氮弓菌、硝化螺旋菌、甲基球菌、梭菌等与土霉素降解和胞外电子传递有密切关系；长期运行中体系均可产生编码“外排泵”基因、编码核糖体保护蛋白基因、编码修饰或钝化土霉素的酶基因，在阳极EABs中产生的抗性基因主要有tetA、 tetC、 tetL、 tetM、 tetW、Tn916/1545、intI 1等，阳极EABs中产生的抗性基因主要有tetA、tetG、tetO、tetX等。.采用电沉积法制备了Fe、Co、Ni等合金电极，Co-Fe表现出最优异的析氢性能。采用简单水热法等方法制备出LDHs、MOF、COF及MXene等的改性材料，进行催化氧还原性能提升探究。已成功制备出NiFe-LDH@Co3O4、CNT/NiCoAl-LDH、NiAl-LDH/GO@ZIF-67、NiCoAl-LDH/MXene等并应用于微生物电化学体系的催化氧还原性能提升，结果表明改性材料具有良好的催化氧还原能力，可大大提升阴极性能进而提升整体性能，为微生物电化学体系的发展开展了系列铺垫工作。此外，开展了纳米材料耦合光合微生物对典型印染废水的污染物降解机制探究，开展了纳米材料对典型微藻（米氏凯轮藻和铜绿微囊藻）的界面相互作用探究，均展现出较大的应用价值和潜力。. 本项目对于电活性生物膜实现抗生素的降解及产能、促进微生物电化学体系的催化氧还原能力做了系列研究工作，为抗生素的微生物电化学技术降解提供部分理论依据和技术支撑。