Three strains of thermophilic green sulfur bacteria (GSB) are known; all are from microbial mats in hot springs in Rotorua, New Zealand (NZ) and belong to the species . Here, we describe diverse populations of GSB inhabiting Travel Lodge Spring (TLS) (NZ) and hot springs ranging from 36.1 °C to 51.
View Article and Find Full Text PDFDehalococcoides mccartyi strain JNA detoxifies highly chlorinated polychlorinated biphenyl (PCB) mixtures via 85 distinct dechlorination reactions, suggesting that it has great potential for PCB bioremediation. However, its genomic and functional gene information remain unknown due to extremely slow growth of strain JNA with PCBs. In this study, we used tetracholorethene (PCE) as an alternative electron acceptor to grow sufficient biomass of strain JNA for subsequent genome sequencing and functional gene identification.
View Article and Find Full Text PDFPentachlorophenol and other chlorinated phenols are highly toxic ubiquitous environmental pollutants. Using gas chromatographic analysis we determined that Dehalococcoides mccartyi strain JNA in pure culture dechlorinated pentachlorophenol to 3,5-dichlorophenol (DCP) via removal of the ortho and para chlorines in all of the three possible pathways. In addition, JNA dechlorinated 2,3,4,6-tetrachlorophenol via 2,4,6-trichlorophenol (TCP) and 2,4,5-TCP to 2,4-DCP and 3,4-DCP, respectively, and dechlorinated 2,3,6-TCP to 3-chlorophenol (CP) via 2,5-DCP.
View Article and Find Full Text PDFWe isolated Dehalococcoides mccartyi strain JNA from the JN mixed culture which was enriched and maintained using the highly chlorinated commercial PCB mixture Aroclor 1260 for organohalide respiration. For isolation we grew the culture in minimal liquid medium with 2,2',3,3',6,6'-hexachlorobiphenyl (236-236-CB)(20 μM) as respiratory electron acceptor. We repeatedly carried out serial dilutions to extinction and recovered dechlorination activity from transfers of 10(-7) and 10(-8) dilutions.
View Article and Find Full Text PDF"Dehalococcoides" sp. strain CBDB1 in pure culture dechlorinates a wide range of PCB congeners with three to eight chlorine substituents. Congener-specific high-resolution gas chromatography revealed that CBDB1 extensively dechlorinated both Aroclor 1248 and Aroclor 1260 after four months of incubation.
View Article and Find Full Text PDFThe history of anaerobic microbial polychlorinated biphenyl (PCB) dechlorination is traced over 20 years using a case study of PCB dechlorination in the Housatonic River (Massachusetts) as an example. The history progresses from the characterization of the PCBs in the sediment, to cultivation in sediment microcosms, to the identification of four distinct types of PCB dechlorination, to a successful field test, to the cultivation in defined medium of the organisms responsible for extensive dechlorination of Aroclor 1260, and finally to the identification of a Dehalococcoides population that links its growth to the dechlorination of Aroclor 1260. Other PCB dechlorinators have also been identified.
View Article and Find Full Text PDFMicrobial reductive dechlorination of commercial polychlorinated biphenyl (PCB) mixtures (e.g., Aroclors) in aquatic sediments is crucial to achieve detoxification.
View Article and Find Full Text PDFWe have developed sediment-free anaerobic enrichment cultures that dechlorinate a broad spectrum of highly chlorinated polychlorinated biphenyls (PCBs). The cultures were developed from Aroclor 1260-contaminated sediment from the Housatonic River in Lenox, MA. Sediment slurries were primed with 2,6-dibromobiphenyl to stimulate Process N dechlorination (primarily meta dechlorination), and sediment was gradually removed by successive transfers (10%) to minimal medium.
View Article and Find Full Text PDFEnviron Sci Technol
September 2005
We have characterized the substrate range of Process LP, a PCB dechlorination activity mediated by anaerobic bacteria, in Housatonic River sediment (Lenox, MA). Process LP has the rare ability to remove unflanked para chlorines from polychlorinated biphenyls (PCBs). We used 2,6-difluoro-4-chlorobiphenyl (DFCB) to activate Process LP in anoxic sediment microcosms and tested its ability to dechlorinate 34 potential PCB substrates, all of which are significant components of PCB mixtures found in contaminated sediments.
View Article and Find Full Text PDF