甲烷化反硝化耦合体系中氟喹诺酮类抗生素降解机理研究

Fluoroquinolone antibiotics are a type of persistent organic pollutants in the environment due to their stable structure and degradation-resistant, which may pose a potential risk on the ecological environment and human health. Immediate research should be conducted to explore pollution control techniques of fluoroquinolone antibiotics. The biological treatment techniques are important means to reduce organic pollutants in sewage, and among them, the integrated methanogenesis and denitrification coupling treatment system can be used to strengthen the removal of persistent organic compounds, carbon and nitrogen. However, it’s unclear whether the system can effectively remove antibiotics from wastewater. This proposal plans to investigate the degradation mechanism of fluoroquinolone antibiotics in the integrated methanogenesis and denitrification coupling treatment system: (1) to optimize the operating conditions of the integrated methanogenesis and denitrification coupling treatment system and evaluate the removal efficiencies of antibiotics; (2) to study the degradation kinetics of fluoroquinolone antibiotics, and identify degradation products and biotransformation pathways using high-resolution chromatography mass spectrometry (HPLC-Q-TOF-MS/MS) method; (3) to explore the metabolic characteristics, community structure and function of the microbes and identify the key degrading microbial populations by using q-PCR and metagenomic sequencing technique. Through the above studies, the control factors and degradation mechanism of fluoroquinolone antibiotics in the integrated methanogenesis and denitrification coupling treatment system should be revealed, which will provide the scientific basis and technical support for the pollution control of fluoroquinolone antibiotics.

氟喹诺酮类抗生素因其结构稳定、难降解，在环境中持久残留，对生态环境及人类健康造成潜在巨大危害，有必要开展其污染控制技术研究。微生物降解法是降低污水中有机污染物的重要技术手段，其中甲烷化反硝化耦合体系可用于强化碳、氮和难降解有机物的去除。该系统是否能够有效去除抗生素尚不清楚。本项目拟以典型氟喹诺酮类抗生素为研究对象，构建甲烷化反硝化耦合处理系统，研究该系统中氟喹诺酮类抗生素的降解机理。优化甲烷化反硝化耦合体系运行条件，评估抗生素去除效能。利用高分辨色谱质谱技术，研究氟喹诺酮类抗生素降解动力学过程，鉴定降解产物，推测其转化途径，同时利用荧光定量PCR和宏基因组测序技术，探究系统中微生物代谢特性及结构和功能，辨识抗生素关键降解微生物种群。通过上述研究，明确甲烷化反硝化耦合体系中氟喹诺酮类抗生素降解控制因子，揭示其降解机理。本研究将为氟喹诺酮类抗生素污染控制提供科学依据和技术支撑。

抗生素在多种环境介质中广泛检出，属典型新污染物，其环境风险引起关注。为有效控制抗生素的传播和扩散，亟需寻找新型污水生物处理技术或方法以强化抗生素去除。本研究在前期工作的基础上，构建甲烷化反硝化耦合处理体系并实现连续运行，初步明确耦合处理体系中碳、氮转化类型及甲烷化菌群及代谢抑制效应。研究发现污泥吸附和生物降解是甲烷化反硝化耦合处理体系氟喹诺酮类抗生素去除的重要路径，其中生物降解起主要作用。耦合处理体系氟喹诺酮类抗生素生物降解主要发生在哌嗪环结构，其中喹诺酮结构较难以被生物代谢，反硝化代谢可能是生物降解的主要途径。高浓度氟喹诺酮类抗生素会对甲烷化反硝化耦合体系碳氮代谢产生抑制效应。16S rDNA高通量测序发现在耦合处理过程中优势细菌菌群为变形菌门（Proteobacteria）、拟杆菌门（Bacteroidetes）、厚壁菌门（Firmicutes）、绿弯菌门（Chloroflexi）和螺旋菌门（Spirochaetes），主要甲烷化微生物为甲烷鬃毛菌属（Methanosaeta）和甲烷杆菌属（Methanobacterium）。此外，本项目中建立了多种基于深度学习算法的水质软测量模型，实现了耦合处理系统出水水质及过程关键控制参数优化；开发了耦合处理系统中复合功能微生物菌群包埋及生物强化处理技术，实现耦合处理系统微生物菌群固定富集。上述研究成果将为污废水甲烷化反硝化耦合处理技术在新污染物（抗生素）管控及污染控制等方面的拓展应用及推广提供重要支撑和保障。