环状和复杂分支结构环烷酸类污染物的好氧/厌氧微生物协同降解及产能耦合机制研究

The naphthenic acids in crude and oil sands have a great variety of species and complicated structures, and impose toxic effect on ecological environment and lives. The polycyclic structure and complex alkyl branch are difficult to degraded, constraining the total degradation efficiency of naphthenic acids. Biodegradation is believed to be one of the most sustainable promising degradation methods due to its cost efficiency, friend to environment and strong practicability. However, it is still challenging to reveal the biodegradation mechanisms controlling the breakdown of cyclic structure and complex alkyl branch. This project intends to study the aerobic and anaerobic biodegradation of cyclic structure, complex alkyl branch. The main purpose is to analyze the pathway and dynamic theory of complex naphthenic acids degradation by measurement of metabolite and characterization of physiological and biochemical activity, explore the biological metabolic pathways and metabolic regulation mechanisms of complex naphthenic acids, clarify the interaction between microbial productivity and complex naphthenic acid metabolism, reveal the coupling mechanisms between complex naphthenic acids removal and anaerobic capacity, and lay a theoretical and technical foundation for improving the energy/resource efficiency of polycyclic structure and complex alkyl branch. The implementation of this project has great significance for the promotion and application of aerobic and anaerobic biodegradation of high acid-containing wastewater in oilfield.

原油及油砂中环烷酸类污染物种类繁多且结构复杂，对生态环境和生物体具有极大的毒害作用，其中多环结构和复杂的烷基侧链分支结构难以降解，制约着环烷酸总体降解效果。微生物降解污染物经济、环保、可推广性强、最具可持续发展前景，然而微生物降解环状结构和复杂分支结构环烷酸的机理尚不明确。本项目针对基于好氧/厌氧微生物协同处理环状和复杂分支环烷酸类物质的过程，通过代谢产物检测和微生物生理生化活性表征等手段，进行复杂结构环烷酸降解途径和降解动力学分析以及厌氧生物产能代谢调控机制研究，努力探索复杂结构环烷酸类物质的生物代谢途径和代谢调控机理，明确微生物产能与复杂结构环烷酸代谢的相互作用规律，揭示基于好氧/厌氧微生物群落构建的复杂结构环烷酸类物质降解和厌氧产能耦合机制研究，为提高环状和复杂分支结构环烷酸能源/资源化处理效率奠定理论和技术基础。项目实施对好氧/厌氧生物处理高含酸原油废水技术的推广应用具有重要意义。

本项目采用臭氧预处理结合固定膜活性污泥反应器（IFAS）处理含有环烷酸的油砂废水（OSPW）。经过11个月的运行，原OSPW-IFAS中12.1%的酸性可提取组分（AEF）和43.1%的母体NA被去除，而臭氧处理的OSPW-IFAS中42.0%的AEF和80.2%的母体NA被去除。UPLC/HRMS分析表明，随着NA环化数的增加，NA的生物降解率明显下降。共聚焦激光扫描显微镜（CLSM）结果显示，经过臭氧处理的OSPW-IFAS中的生物膜（94±1.6微米）明显比原始OSPW-IFAS中的生物膜（72±2.8微米）厚，经过283天的培养。定量聚合酶链反应（q-PCR）显示，在原OSPW-IFAS系统中，生物膜中硝化器基因（aomA、NSR和Nitro）和脱硝器基因（narG、nirS、nirK和nosZ）的丰度比例都明显高于絮状物，但在臭氧处理的OSPW-IFAS系统中却出现了不同的趋势。454测序的微生物群落分析显示，蛋白质细菌、硝化细菌、酸性细菌和类细菌在IFAS反应器的絮状物和生物膜中都是占优势的门类。进一步优化IFAS系统，评估了水力停留时间（HRT）和COD/N比对OSPW处理性能的影响。经过11个月的水力停留时间和铵的优化，在原OSPW-IFAS中，54.56%的COD和30.20%的AEF被去除，而在臭氧OSPW-IFAS中，56.83%的COD和51.51%的AEF被去除。延长IFAS中的HRT对COD和氮的去除没有明显影响，而较低的COD/N比率则增加了有机物和总氮的去除。定量聚合酶链反应（q-PCR）表明，在HRT优化过程中，硝化器和反硝化器基因的丰度下降，而在铵盐优化后则明显增加。