title: Sulfidogenesis in hypersaline chloride-sulfate lakes of Kulunda Steppe (Altai, Russia).
abstract: The activity and culturable diversity of sulfidogens were investigated in anoxic sediments of four hypersaline lakes with pH 7.6-8.2 in the Kulunda Steppe (Altai, Russia). Sulfate reduction rates were low, varying from 0.1 to 6.0 nmol HS(-) /(cm(3) h) with a maximum in the top 10 cm layer. Potential sulfidogenic rates with thiosulfate and sulfur as the e-acceptors were higher than with sulfate and were stimulated by formate, lactate, and acetate. Sulfidogenesis was optimal at salt concentrations below 2 M NaCl. Cultivation at 2 M NaCl resulted in the isolation of several strains of moderately halophilic SRB, but no growth of SRB was observed at 4 M NaCl. At lithotrophic conditions (i.e., with formate or H(2) as e-donors), several closely related alkalitolerant strains belonging to the genus Desulfonatronovibrio were isolated. Enrichments at heterotrophic conditions with lactate, propionate, acetate, or butyrate using sulfate or thiosulfate as e-acceptors yielded isolates related to Desulfosalsimonas propionicica, Desulfohalobium utahense, and Desulfocella halophila. Sulfur-reducing enrichments at 2 M NaCl with ethanol produced a member of the genus Halanaerobium, while enrichments at 4 M NaCl with acetate were dominated by archaea, demonstrating for the first time such type of catabolism in haloarchaea.
authors.affiliation: Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia. soroc@inmi.ru
authors.forename: Dimitry Y
authors.initials: DY
authors.lastname: Sorokin
authors.forename: Elena E
authors.initials: EE
authors.lastname: Zacharova
authors.forename: Nikolai V
authors.initials: NV
authors.lastname: Pimenov
authors.forename: Tatjana P
authors.initials: TP
authors.lastname: Tourova
authors.forename: Anjela N
authors.initials: AN
authors.lastname: Panteleeva
authors.forename: Gerard
authors.initials: G
authors.lastname: Muyzer
mesh_terms: D001105:Archaea / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D020564:Deltaproteobacteria / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D060106:Lakes / Q000737:chemistry / Q000382:microbiology*; D010802:Phylogeny; D012426:Russia; D012492:Salts; D012965:Sodium Chloride / Q000032:analysis; D013431:Sulfates / Q000032:analysis / Q000378:metabolism*; D013455:Sulfur / Q000032:analysis / Q000378:metabolism; D016999:Sulfur-Reducing Bacteria / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013885:Thiosulfates / Q000032:analysis / Q000378:metabolism
chemical_list: D012492:Salts; D013431:Sulfates; D013885:Thiosulfates; D012965:Sodium Chloride; D013455:Sulfur