Dechlorination of Chlorobenzenes by a Culture Containing Bacterium DF-1, a PCB Dechlorinating Microorganism

• Published in: Environmental science & technology Vol. 36; no. 15; pp. 3290 - 3294
• Main Authors: Wu, Qingzhong, Milliken, Charles E, Meier, G. Patrick, Watts, Joy E. M, Sowers, Kevin R, May, Harold D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-08-2002
• Subjects: Applied sciences; Bacteria; Biological and physicochemical phenomena; Biological and physicochemical properties of pollutants. Interaction in the soil; Chlorine - chemistry; Chlorobenzenes - metabolism; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental impact; Environmental Pollutants - metabolism; Exact sciences and technology; Hydroxylation; Natural water pollution; PCB; Pollution; Pollution, environment geology; Polychlorinated biphenyls; Polychlorinated Biphenyls - metabolism; Soil and sediments pollution; Water treatment and pollution; Biodegradation; Microbial activity; Dechlorination; Pollutant behavior; Organochlorine compounds; Chlorine Organic compounds; Bacteria; Aromatic compound; Identification; Water pollution; Metabolic pathway; Sediments
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es0158612

Polychlorinated benzenes were reductively dechlorinated by an enrichment culture containing the polychlorinated biphenyl (PCB) dechlorinating bacterium DF-1. The culture dechlorinated hexachlorobenzene (hexa-CB) → pentachlorobenzene (penta-CB) → 1,2,3,5-tetrachlorobenzene (1,2,3,5-CB) → 1,3,5-trichlorobenzene (1,3,5-CB) and did not dechlorinate other tetrachlorobenzenes or any trichlorobenzenes. This restricted series of reactions is the most predominant and frequently reported pathway for the dechlorination of hexa-CB and penta-CB by enrichment cultures inoculated with either freshwater or estuarine sediments. The culture did not dechlorinate hydroxylated and methoxylated polychlorinated benzenes or a hydroxylated PCB. Bacterium DF-1 was detected by PCR/DGGE analysis following dechlorination of penta-CB but was not detected when a chlorinated benzene (CB) was not dechlorinated; detection of other members in the community was unaffected by the presence or absence of CB dechlorination. This is the first report of a bacterium that reductively dechlorinates both PCBs and CBs and the first identification of an organism that can dechlorinate a CB with more than four chlorines.