多环芳烃（PAHs）是土壤中广泛存在的有机污染物，其“三致”效应会危及土壤生态安全与人体健康，是亟需解决的土壤环境问题。微生物强化降解是一种环境友好、经济高效的土壤修复技术。国内外学者对好氧条件下微生物降解土壤PAHs已开展了较为系统的科研工作，而厌氧条件下微生物降解土壤PAHs的过程则有待深入研究，包括：还原反应的特定体系、PAHs微生物可利用性的变化、电子受体的供给情况及厌氧微生物群落的响应过程等。本项目拟在纯厌氧环境中，向污染土壤添加不同浓度的PAHs微生物可利用性促进剂（甲基β环糊精）和电子受体（硝态氮），运用定量化的数学模型、13C-PAHs稳定性同位素探针和高通量测序等方法，从土壤化学和微生物学角度，揭示甲基β环糊精强化土壤PAHs反硝化厌氧降解机制，阐释影响厌氧降解进程的关键限制因素，探明体系内厌氧微生物群落的响应过程，为研究土壤PAHs厌氧降解修复提供理论指导和科学依据。

Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in soils. Pollution with persistent PAHs has threatened soil ecological safety and human health and has been becoming a big environmental problem. Therefore, remediation of PAH-contaminated soil has become one crucial issue which needs to be solved. Enhanced microbial degradation is considered as one of environmental and cost effective technologies for the remediation of PAH-contaminated soils. Compared with the widely studied PAHs biodegradation under aerobic conditions, much less attention has been paid to the anaerobic biodegradation of PAHs. Furthermore, the lack of oxygen under anaerobic condition makes PAHs degradation extremely difficult and critical biochemical processes during anaerobic degradation process, including specific reduction system, provision of alternate electron acceptors, changes of PAHs bioaccessibility and the relationship among different microbial functioning communities, remain largely unknown. Therefore, anaerobic microcosm study will be set, combining Response Surface Methodology, a first-three-compartment conceptual model, the stable isotope probing, and the high throughout sequencing technologies to systematically investigate the role of methyl-β-cyclodextrin in the enhanced anaerobic biodegradation of PAHs in soils under nitrate reducing condition. From the perspective of soil microbiology and soil chemistry, the PAHs degradation dynamics, the rate-limiting factors, and the response mechanism of different microbial functioning communities will be clarified during the bioremediation. This study will provide important theoretical direction and scientific evidence for the application of the enhanced anaerobic bioremediation technology of PAHs in soils.