Bacterial dehalorespiration with chlorinated benzenes

• Published in: Nature (London) 2000-11, Vol.408 (6812), p.580-583
• Main Authors: Adrian, Lorenz, Szewzyk, Ulrich, Wecke, Jörg, Görisch, Helmut
• Format: Article
• Language: English
• Subjects: Aerobic bacteria; Anaerobic conditions; Bacteria; Bacteria - classification; Bacteria - isolation & purification; Bacteria - metabolism; Bacteria - ultrastructure; Bacteriology; Biodegradation of pollutants; Biological and medical sciences; Biotechnology; Chlorobenzene; Chlorobenzenes - metabolism; Contaminants; Culture Media; Dechlorination; Dehalococcoides ethenogenes; Environment and pollution; Fundamental and applied biological sciences. Psychology; Genes; Gram-Negative Bacteria - classification; Gram-Negative Bacteria - metabolism; Gram-Negative Bacteria - ultrastructure; Gram-Positive Bacteria - classification; Gram-Positive Bacteria - metabolism; Gram-Positive Bacteria - ultrastructure; Humanities and Social Sciences; Hydrocarbons; Industrial applications and implications. Economical aspects; letter; Metabolism. Enzymes; Microbiology; Molecular Sequence Data; multidisciplinary; Phylogeny; RNA, Bacterial - genetics; RNA, Ribosomal, 16S - genetics; Science; Science (multidisciplinary); trichlorobenzene
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/35046063

Chlorobenzenes are toxic, highly persistent and ubiquitously distributed environmental contaminants that accumulate in the food chain 1 . The only known microbial transformation of 1,2,3,5-tetrachlorobenzene (TeCB) and higher chlorinated benzenes is the reductive dechlorination to lower chlorinated benzenes under anaerobic conditions observed with mixed bacterial cultures 2 , 3 , 4 . The lower chlorinated benzenes can subsequently be mineralized by aerobic bacteria. Here we describe the isolation of the oxygen-sensitive strain CBDB1, a pure culture capable of reductive dechlorination of chlorobenzenes. Strain CBDB1 is a highly specialized bacterium that stoichiometrically dechlorinates 1,2,3-trichlorobenzene (TCB), 1,2,4-TCB, 1,2,3,4-TeCB, 1,2,3,5-TeCB and 1,2,4,5-TeCB to dichlorobenzenes or 1,3,5-TCB. The presence of chlorobenzene as an electron acceptor and hydrogen as an electron donor is essential for growth, and indicates that strain CBDB1 meets its energy needs by a dehalorespiratory process. According to their 16S rRNA gene sequences, strain CBDB1, Dehalococcoides ethenogenes 5 and several uncultivated bacteria form a new bacterial cluster, of which strain CBDB1 is the first, so far, to thrive on a purely synthetic medium.