title: Thiohalomonas denitrificans gen. nov., sp. nov. and Thiohalomonas nitratireducens sp. nov., novel obligately chemolithoautotrophic, moderately halophilic, thiodenitrifying Gammaproteobacteria from hypersaline habitats.
abstract: A novel group of moderately halophilic, obligately chemolithoautotrophic, sulfur-oxidizing Gammaproteobacteria was found in sediments of various inland hypersaline lakes and a solar saltern. These bacteria were enriched and isolated with thiosulfate as electron donor and nitrate as electron acceptor at 2 M NaCl. Ten isolates (HLD strains) were long non-motile rods. They grew anaerobically as complete denitrifiers, and aerobically under micro-oxic conditions. Sulfate was the final product of thiosulfate and sulfide oxidation, and nitrite and N(2)O were intermediates of nitrate reduction to N(2). The HLD strains grew optimally at pH 7.3-7.8, and at NaCl concentrations of 1.5-2.0 M. On the basis of phenotypic and genetic analysis, the moderately halophilic, thiodenitrifying isolates are proposed to be assigned to a new genus and species, Thiohalomonas denitrificans gen. nov., sp. nov. The type strain is HLD 2(T) (=DSM 15841(T)=UNIQEM U222(T) ). A single strain, HRhD 3sp(T), with vibrio-shaped cells, was obtained from a co-culture capable of complete denitrification of nitrate in the presence of either thiocyanate or thiosulfate as electron donor. It grew anaerobically with thiosulfate, reducing nitrate to nitrite, or under micro-oxic conditions at 1.0-2.5 M NaCl with an optimum at 1.0 M. Strain HRhD 3sp(T) was genetically related to the HLD strains at the level of a separate species and is described as Thiohalomonas nitratireducens sp. nov. The type strain is HRhD 3sp(T) (=DSM 16925(T)=UNIQEM U248(T)).
authors.affiliation: Department of Environmental Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.|Winogradsky Institute of Microbiology, Russian Academy of Sciences, Prospect 60-let Octyabrya 7/2, 117811 Moscow, Russia.
authors.forename: Dimitry Yu
authors.initials: DY
authors.lastname: Sorokin
authors.affiliation: Winogradsky Institute of Microbiology, Russian Academy of Sciences, Prospect 60-let Octyabrya 7/2, 117811 Moscow, Russia.
authors.forename: Tatjana P
authors.initials: TP
authors.lastname: Tourova
authors.affiliation: MPI für Terrestrische Mikrobiologie, Karl-von-Frisch-Straße, D-35043 Marburg, Germany.
authors.forename: Gesche
authors.initials: G
authors.lastname: Braker
authors.affiliation: Department of Environmental Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
authors.forename: Gerard
authors.initials: G
authors.lastname: Muyzer
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001482:Base Composition; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis; D020563:Gammaproteobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D020459:Genes, rRNA; D019015:Geologic Sediments / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D008124:Locomotion; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D012965:Sodium Chloride / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism*; D013885:Thiosulfates / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D009566:Nitrates; D009573:Nitrites; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013885:Thiosulfates; D012965:Sodium Chloride; D013455:Sulfur; D009584:Nitrogen