TCE reductive dehalogenation by a microbial community

微生物群落的 TCE 还原脱卤

• 批准号: 6443982
• 负责人: Margaret Romine
• 金额: $ 10.08万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2002-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6443982
• 关键词: biotransformation; chemical kinetics; chlorine; environmental contamination; environmental toxicology; enzyme activity; ethylenes; gene expression; ground water; halobiphenyl /halotriphenyl compound; halogenation; hazardous substances; hydrolase; microorganism culture; polymerase chain reaction; trichloroethylene; waste treatment

Tetrachloroethene (PCE) and trichloroethene (TCE) are common groundwater contaminants. Under anaerobic conditions these solvents are are transformed by biological reductive dechlorination to dichloroethene isomers (DCEs), vinyl chloride (VC) and sometimes ethene. The original contaminants and their intermediate metabolites are all CERCLA listed hazardous chemicals that are neurotoxic or carcinogenic. Determining the extent of dechlorination under different conditions would be helpful for evaluating the human health risk at individual sites. Ideally, the conditions which promote complete dechlorination to ethene should be ascertained. These conditions are currently unclear and it is this gap in scientific knowledge which this project is designed to address. This project will utilize an enrichment culture developed by Jim Gossett and Steve Zinder at Cornell University, which is known to completely dechlorinate high concentrations of PCE (0.55 mM) and other chlorinated ethenes to ethene. A specific aim of this project is to develop molecular probes that target 16S rRNA genes and reductive dehalogenase genes present in the culture. These probes will be useful for study of the dynamics of the bacterial community and the expression of the dehalogenases in the culture, as electron donors/acceptors and other nutrients are varied. The goal is to find the optimum conditions for dechlorination of PCE, TCE, DCE and especially VC, which accumulates due to its slow rate of dechlorination. The members of the community will be phylogenetically characterized by 16S rRNA typing. Syntrophic relationships between the dechlorinator, Dehalococcoides ethenogenes, and other species will be established by experimentally combining defined members of the community. Presumably, the syntrophic organisms supply electron donor (hydrogen) and nutrients to D. ethenogenes, so these studies will help further define the conditions which produce optimal dechlorination. The presence of other dechlorinators in the Cornell enrichment culture and the anaerobic enrichment culture from Corvalis, Oregon will be assessed by restriction fragment analysis of amplified 16S rRNA, sequencing of selected clones and searching for homology with known dechlorinators. This may lead to the discovery of organisms which dechlorinate VC at a faster rate, or dechlorinate other substrates under different conditions than are optimal for D. ethenogenes.

四氯乙烯（PCE）和三氯乙烯（TCE）是常见的地下水污染物。在厌氧条件下，这些溶剂通过生物还原脱氯为二氯乙烯（DCES），氯化乙烯基（VC），有时甚至是乙烯转化。原始污染物及其中间代谢物都是Cercla列出的有害化学物质，这些化学物质是神经毒性或致癌性的。在不同条件下确定脱氯的程度将有助于评估各个部位的人类健康风险。理想情况下，应确定促进乙烯完全脱氯的条件。这些条件目前尚不清楚，这是该项目旨在解决的科学知识的差距。该项目将利用康奈尔大学吉姆·戈塞特（Jim Gossett）和史蒂夫·辛德（Steve Zinder）开发的富集文化，康奈尔大学（Cornell University）已众所周知，该培养物完全是氯酸酯高浓度的PCE（0.55 mm）和其他氯化乙烯的浓度。该项目的一个具体目的是开发靶向16S rRNA基因和还存在培养物中的还原性去留他酶基因的分子探针。这些探针将有助于研究细菌群落的动力学和培养基中脱核酶的表达，因为电子供体/受体和其他营养素的变化是不同的。目的是找到PCE，TCE，DCE尤其是VC的氯化的最佳条件，该条件由于其缓慢的氯化速度而累积。社区成员将以16S rRNA键入为特征。脱绿氯，去核苷的乙烯基因和其他物种之间的综合性关系将通过实验结合社区的定义成员来建立。据推测，综合症生物为乙烯基因链球菌提供电子供体（氢）和营养，因此这些研究将有助于进一步定义产生最佳脱氯的条件。俄勒冈州科瓦利斯（Corvalis）的康奈尔富集培养物和厌氧富集培养物在俄勒冈州的厌氧富集培养物中的存在将通过限制性碎片分析进行评估。这可能会导致发现以更快的速率脱氯的生物，或者在不同条件下与乙烯基因生成蛋白原相比，在不同条件下脱氯酸盐的其他底物。