脱卤拟球菌还原性降解地下水中氯代乙烯的过程及机理研究

氯代乙烯在工农业中应用广泛，对水环境和人类健康潜在威胁极大。在地下水中，脱卤拟球菌是目前唯一能将氯代乙烯还原成无毒产物乙烯的细菌。但其降解氯代乙烯的微生物机理，以及添加外源脱卤拟球菌进行原位修复时其与土著微生物的竞争关系尚未明确。针对这些问题，项目拟通过13C自然丰度测定、荧光定量PCR、克隆/测序等手段研究地下水中脱卤拟球菌降解氯代乙烯的途径及机理。并阐明脱卤拟球菌、含氧量、pH、有机碳、氧化还原电位与氯代乙烯修复的内在关系，明确影响脱卤拟球菌还原氯代乙烯的关键生物地球化学指标。利用选择性培养基筛选出环境适应力强的脱卤拟球菌为原位修复提供高效降解菌。纯化鉴定关键的还原脱卤酶，研究其酶学特性及降解机理。将扩大培养的高效降解菌接种到氯代乙烯污染地下水区域，利用活性脱卤拟球菌进行修复并通过高通量测序研究土著微生物群落组成变化。项目有望为脱卤拟球菌在地下水污染修复中的应用提供理论依据与实践方法。

Chlorinated ethenes have been wildly applied in manufacturing and agriculture, which pose a great potential threat to the water environment and human health. In groundwater environment, Dehalococcoides is the only known bacteria that can reduce chlorinated ethenes to non-toxic ethene. However, the microbial mechanism of Dehalococcoides in the degradation of chlorinated ethenes, as well as the competitive relationship between exogenous Dehalococcoides and in situ microorganisms has not yet clear. In view of these problems, this project aims to study the pathways and mechanisms of the degradation of chlorinated ethenes in the groundwater via the detection of 13C isotopic natural abundance, fluorescence quantitative PCR and cloning/sequencing. Better understanding of the intrinsic relationship between Dehalococcoides, oxygen content, pH, organic carbon content, redox potential and the remediation of chlorinated ethenes, in order to clarify the key biogeochemical indexes that affect the reduction of chlorinated ethenes by Dehalococcoides. To obtain the microbes with high degrading efficiency for in situ bioremediation, selective medium has been applied to screen out the Dehalococcoides with high environmental adaptability. Key reductive dehalogenase have been purified and identified to study its enzymatic properties and degradation mechanism. The culture with high degrading efficiency has been inoculated into the contaminated groundwater site for remediation by active Dehalococcodies, and the high-throughput sequencing is applied to study the change of indigenous microbial community composition. The research results of this project is expected to provide theoretical basis and practical strategy for the application of Dehalococcoides in the bioremediation of groundwater contaminants.