title: Two anaerobic polychlorinated biphenyl-dehalogenating enrichments that exhibit different para-dechlorination specificities.
abstract: Two anaerobic polychlorinated biphenyl (PCB)-dechlorinating enrichments with distinct substrate specificities were obtained: a 2,3,4,6-tetrachlorobiphenyl (2346-CB) para-dechlorinating enrichment derived from Aroclor 1260-contaminated Woods Pond (Lenox, Mass.) sediment and a 2,4,6-trichlorobiphenyl (246-CB) unflanked para-dechlorinating enrichment derived from PCB-free Sandy Creek Nature Center (Athens, Ga.) sediment. The enrichments have been successfully transferred to autoclaved soil slurries over 20 times by using 300 to 350 microM 2346-CB or 246-CB. Both enrichments required soil for successful transfer of dechlorination activity. The 2346-CB enrichment para dehalogenated, in the absence or presence of 2346-CB, only 4 of 25 tested para halogen-containing congeners: 234-CB, 2345-CB, 2346-CB, and 2,4,6-tribromobiphenyl (246-BrB). In the presence of 246-CB, the 246-CB enrichment para dehalogenated 23 of the 25 tested congeners. However, only three congeners (34-CB, 2346-CB, and 246-BrB) were dehalogenated in the absence of 246-CB, indicating that these specific congeners initiate dehalogenation in this enrichment culture. The addition of the 2346-CB (para)-dechlorinating enrichment did not further stimulate the 2346-CB-primed dechlorination of the Aroclor 1260 residue in Woods Pond sediment samples. Compared to the addition of the primer 246-CB or the 246-CB unflanked para-dechlorinating enrichment alone, the addition of both 246-CB (300 microM) and the 246-CB enrichment stimulated the unflanked para dechlorination of the Aroclor 1260 residue in Woods Pond sediments. These results indicate that the two enrichments contain different PCB-dechlorinating organisms, each with high substrate specificities. Furthermore, bioaugmentation with the enrichment alone did not stimulate the desired dechlorination in PCB-contaminated Woods Pond sediment.
authors.affiliation: Department of Microbiology, University of Georgia, Athens 30602, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Wu
authors.forename: J
authors.initials: J
authors.lastname: Wiegel
mesh_terms: D000693:Anaerobiosis; D001140:Aroclors / Q000737:chemistry / Q000378:metabolism; D001673:Biodegradation, Environmental; D002713:Chlorine / Q000737:chemistry; D004785:Environmental Pollutants / Q000378:metabolism*; D011078:Polychlorinated Biphenyls / Q000737:chemistry / Q000378:metabolism*; D014871:Water Microbiology
chemical_list: D001140:Aroclors; D004785:Environmental Pollutants; C026987:aroclor 1260; D002713:Chlorine; D011078:Polychlorinated Biphenyls