title: Dehalobacter restrictus gen. nov. and sp. nov., a strictly anaerobic bacterium that reductively dechlorinates tetra- and trichloroethene in an anaerobic respiration.
abstract: The highly enriched anaerobic bacterium that couples the reductive dechlorination of tetrachloroethene to growth, previously referred to as PER-K23, was obtained in pure culture and characterized. The bacterium, which does not form spores, is a small, gram-negative rod with one lateral flagellum. It utilized only H2 as an electron donor and tetrachloroethene and trichloroethene as electron acceptors in an anaerobic respiration process; it could not grow fermentatively. Acetate served as a carbon source in a defined medium containing iron as the sole trace element, the two vitamins thiamine and cyanocobalamin, and the three amino acids arginine, histidine, and threonine. The cells contained menaquinones and b-type cytochromes. The G+C content of the DNA was 45.3 +/- 0.3 mol%. The cell wall consisted of type-A3gamma peptidoglycan with ll-diaminopimelic acid and one glycine as an interpeptide bridge. The cells are surrounded by an S-layer; an outer membrane was absent. Comparative sequence analysis of the 16S rRNA sequence showed that PER-K23 is related to gram-positive bacteria with a low G+C content of the DNA. Based on the cytological, physiological, and phylogenetic characterization, it is proposed to affiliate the isolate to a new genus, Dehalobacter, with PER-K23 as the type strain of the new species Dehalobacter restrictus.
authors.affiliation: Swiss Federal Institute for Environmental Science and Technology (EAWAG), Limnological Research Center, CH-6047 Kastanienbaum, Switzerland. christof.holliger@eawag.ch
authors.forename: C
authors.initials: C
authors.lastname: Holliger
authors.forename: D
authors.initials: D
authors.lastname: Hahn
authors.forename: H
authors.initials: H
authors.lastname: Harmsen
authors.forename: W
authors.initials: W
authors.lastname: Ludwig
authors.forename: W
authors.initials: W
authors.lastname: Schumacher
authors.forename: B
authors.initials: B
authors.lastname: Tindall
authors.forename: F
authors.initials: F
authors.lastname: Vazquez
authors.forename: N
authors.initials: N
authors.lastname: Weiss
authors.forename: A J
authors.initials: AJ
authors.lastname: Zehnder
mesh_terms: D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002455:Cell Division / Q000502:physiology; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000032:analysis / Q000235:genetics; D013750:Tetrachloroethylene / Q000378:metabolism*; D014241:Trichloroethylene / Q000378:metabolism*
chemical_list: D012336:RNA, Ribosomal, 16S; D014241:Trichloroethylene; D013750:Tetrachloroethylene