title: Dissulfurimicrobium hydrothermalegen. nov., sp. nov., a thermophilic, autotrophic, sulfur-disproportionating deltaproteobacterium isolated from a hydrothermal pond.
abstract: A thermophilic, anaerobic, chemolithoautotrophic bacterium (strain Sh68T) was isolated from a hydrothermal pond at Uzon Caldera, Kamchatka, Russia, using anoxic medium with elemental sulfur as the only energy source. Cells of strain Sh68Twere Gram-stain-negative rods, 0.5-0.8 μm in diameter and 1.2-2.0 μm in length, motile by means of flagella. The temperature range for growth was 30-65 °C, with an optimum at 50-52 °C. The pH range for growth was 5.2-7.5, with optimum growth at pH 6.0-6.2. Growth of strain Sh68Twas observed at NaCl concentrations ranging from 0 to 2.3 % (w/v). Strain Sh68Tgrew anaerobically with elemental sulfur as an energy source and bicarbonate/CO2as a carbon source. Elemental sulfur was disproportionated to sulfide and sulfate. Growth was enhanced in the presence of poorly crystalline Fe(III) oxide (ferrihydrite) as a sulfide-scavenging agent. Strain Sh68Twas also able to grow by disproportionation of thiosulfate and sulfite. Sulfate was not used as an electron acceptor either with H2or with organic electron donors. Analysis of the 16S rRNA gene sequence revealed that the isolate belongs to the classDeltaproteobacteriaand is related most closely toDissulfuribacter thermophilusS69T(90.0 % similarity). On the basis of its physiological properties and results of phylogenetic analyses, strain Sh68Tis considered to represent a novel species of a new genus, for which the nameDissulfurimicrobium hydrothermalegen. nov., sp. nov. is proposed. The type strain ofDissulfurimicrobium hydrothermaleis Sh68T( = JCM 19990T= VKM B-2854T). This is the first description of a sulfur-disproportionating thermophile from a terrestrial ecosystem.
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Leninskiy Prospect 33 bld. 2, 119071 Moscow, Russia.
authors.forename: A I
authors.initials: AI
authors.lastname: Slobodkin
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Leninskiy Prospect 33 bld. 2, 119071 Moscow, Russia.
authors.forename: G B
authors.initials: GB
authors.lastname: Slobodkina
authors.affiliation: Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Leninskiy Prospect 33 bld. 2, 119071 Moscow, Russia.
authors.forename: A N
authors.initials: AN
authors.lastname: Panteleeva
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Leninskiy Prospect 33 bld. 2, 119071 Moscow, Russia.
authors.forename: N A
authors.initials: NA
authors.lastname: Chernyh
authors.affiliation: Gubkin Russian State University of Oil and Gas, Leninskiy Prospect 65, 117485 Moscow, Russia.
authors.forename: A A
authors.initials: AA
authors.lastname: Novikov
authors.affiliation: Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Leninskiy Prospect 33 bld. 2, 119071 Moscow, Russia.
authors.forename: E A
authors.initials: EA
authors.lastname: Bonch-Osmolovskaya