Isolation and Characterization of PCB Dechlorinators

多氯联苯由于其化学稳定性和疏水性而具有抗氧化性。在多氯联苯污染 生物介导的脱氯作用可降低毒性， 生物累积然而，在环境中，这些化合物生物降解缓慢，不完全，使内在的生物修复不太可取的多氯联苯污染的网站的管理。我们一直在研究一种技术，以刺激在受污染的沉积物中的多氯联苯原位还原脱氯。目前，天然样品中多氯联苯脱氯微生物的总数无法量化;因此，我们无法确定富集和/或刺激技术是否会导致环境中脱氯细菌的生长。如果这些生物被识别，基于分子的技术可以被开发出来，以确定哪些生物存在于特定的地点，以及它们的数量如何随时间变化。此外，在没有多氯联苯脱氯细菌分离株或高度富集和确定的脱氯微生物培养物的情况下，我们对多氯联苯脱氯生理学的理解（例如，生长和生物降解率、营养需求等）是有限的，因此，我们的努力，工程沉积物生物修复系统显着阻碍。在这项拟议的研究中，我们将：（1）开发高度富集的多氯联苯脱氯文化（2-3人口）或获得多氯联苯脱氯分离物从巴尔的摩港，哈德逊河，帕洛斯弗迪斯，沃基贡港沉积物和确定脱氯剂存在，和（2）调查的H2亲和力和阈值，电子供体特异性，电子受体特异性，和PCB同系物特异性的这些生物。

PCBs are recalcitrant due their chemical stability and hydrophobicity. In PCB-contaminated sediments, biologically-mediated dechlorination results in reduced toxicity and less bioaccumulation. In the environment, however, these compounds biodegrade slowly and incompletely, making intrinsic bioremediation less desirable for the management of PCB-contaminated sites. We have been working on a technology to stimulate the in situ reductive dechlorination of PCBs in contaminated sediment. Presently, the total number of PCB-dechlorinating microbes in natural samples cannot be quantified; therefore, we cannot determine whether enrichment and/or stimulation techniques result in the growth of dechlorinating bacteria in the environment. If these organisms are identified, molecular-based techniques could be developed to determine which organisms are present at a particular site and how their numbers change with time. In addition, without PCB-dechlorinating bacterial isolates or highly enriched and defined dechlorinating microbial cultures, our Understanding of the physiology of PCB-dechlorination (e.g., growth and biodegradation rates, nutritional needs, etc.) is limited, and thus our efforts to engineer a sediment bioremediation system are significantly hampered. In this proposed research we will: (1) develop highly enriched PCB-dechlorinating cultures (2-3 populations) or obtain PCB-dechlorinating isolates from Baltimore Harbor, Hudson River, Palos Verdes, and Waukegon Harbor sediment and identify the dechlorinators present, and (2) investigate the H2 affinity and threshold, electron donor specificity, electron acceptor specificity, and PCB congener specificity of these organisms.