填埋场覆盖土中氯代烃双机制生物降解与功能菌群落结构研究

Functional microorganisms with high tolerance can effectively degrade chlorinated hydrocarbons by aerobic pathway from MSW (Municipal Solid Waste) landfill cover soils, which is regarded as an effective way for controlling chlorinated hydrocarbons pollution. It is noted that the autotrophic degradation mechanism played an important role during the degradation of chlorinated hydrocarbon in the landfill cover soil, besides for the well-known heterotrophic co-metabolism mechanism of methanotrophic bacteria. In order to expound the chlorinated hydrocarbon aerobic degradation effect under the dual-mechanism in the microenvironment of cover soils, microbial community structure will be analyzed and the function microbial was acclimatized and screened. Firstly, the original data of function microbial diversity in the typical landfill cover soil will be investigated by physicochemical index detection, chlorinated hydrocarbon domestication and high throughput sequencing analysis. Secondly, under different experiments conditions and technical means, including Q-PCR and T-A cloning, the species and abundance variation of key enzymes during the degradation process will be investigated, and the effect of collaborative growth or competitive inhibition among different bacteria will be identified, then mechanism of chlorinated hydrocarbon degradation will be clarified. Finally, simulated covers with the function of dual-mechanism regulation could be developed, then the degradation kinetics model could deduced and the response relationship between environmental factors and chlorinated hydrocarbon degrading bacteria could be revealed. The research results can enrich the knowledge of pollution soil and microbial ecology, and provide the theoretical foundation for application of bio-degradation of chlorinated hydrocarbon.

填埋场覆盖土中高耐受性功能微生物可通过好氧途径高效降解氯代烃，已成为控制氯代污染物的有效途径。在覆盖土氯代烃降解过程中，除了被广泛认可的甲烷氧化菌异养共代谢机制，申请人前期研究发现氯代烃自养降解机制也起着重要作用。为阐明两种降解机制在覆盖土微生境中的作用与转化规律这一关键问题，拟开展以下研究：通过对典型填埋场覆盖土进行理化性质检测、氯代烃驯化和高通量测序分析，为覆盖土功能微生物群落结构和多样性提供原始数据；开展不同工况下氯代烃降解实验，利用Q-PCR、T-A克隆、纯菌筛选等技术手段，考察关键酶在降解过程中的种类和丰度变化，辨识自养和异养菌群间的协同生长或竞争抑制作用，明晰降解过程主导机制的转换规律；建立具有双机制调控功能的模拟覆盖层，推演垂直梯度氯代烃降解动力学模型，揭示环境因子与氯代烃降解菌群间的响应关系。研究成果可丰富污染土壤与微生物生态学知识，为拓展氯代烃生物降解的应用提供理论基础。

填埋场覆盖土中高耐受性功能微生物可通过好氧途径高效降解氯代烃，已成为控制氯代污染物的有效途径。在覆盖土氯代烃降解过程中，除了被广泛认可的甲烷氧化菌异养共代谢机制，氯代烃自养降解机制也起着重要作用。为阐明两种降解机制在覆盖土微生境中的作用与转化规律这一关键问题，本项目开展了以下研究，首先，全面调研了填埋场氯代烃污染组成、浓度及降解潜力；基于吸附和降解特性，明确了填埋场氯代烃控制限制性因素；分析了典型填埋场覆盖土微生物群落组成及氯代烃降解潜在微生物多样性。其次，对典型生活垃圾填埋场覆盖土进行氯代烃共代谢驯化，考察了驯化前后群落结构特性及变化规律；分析了覆盖土对氯代烃的厌氧/好氧共代谢降解能力，拟合一阶动力学常数；筛选分离了具有氯代烃降解功能的异养和自养微生物。最后，构建了具有双机制调控功能的覆盖层氯代烃降解模拟系统，基于分子生物学技术考察了氯代烃降解关键酶基因pmoA的分布特性，氯代烃降解功能菌分布特性，明晰了覆盖层典型氯代烯烃降解过程的主导机制及转化规律。本项目还开展了一系列富有成效的学术交流活动，三年来，在基金的支持下，出版学术著作2部（其中主编1部中文著作，参编1部英文著作）；申请国家专利5项（已授权3项，已公开2项）；已发表论文15篇（其中7篇为SCI、EI论文，8篇为CSCD核心源刊论文）。本项目研究成果已在国内外同行中产生重要影响，研究成果最终为填埋场等氯代烃污染场地的原位生物修复提供科学依据，对推动氯代烃污染控制新技术的工程应用提供理论指导和实践基础。