Original Paper

Extremophiles

, Volume 16, Issue 2, pp 245-253

First online:

Thermotomaculum hydrothermale gen. nov., sp. nov., a novel heterotrophic thermophile within the phylum Acidobacteria from a deep-sea hydrothermal vent chimney in the Southern Okinawa Trough

  • Hiroshi IzumiAffiliated withLaboratory of Microbiology, Faculty of Fisheries Sciences, Hokkaido University
  • , Takuro NunouraAffiliated withSubsurface Geobiology Advanced Research (SUGAR) Project, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • , Masayuki MiyazakiAffiliated withSubsurface Geobiology Advanced Research (SUGAR) Project, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • , Sayaka MinoAffiliated withLaboratory of Microbiology, Faculty of Fisheries Sciences, Hokkaido University
  • , Tomohiro TokiAffiliated withFaculty of Science, University of the Ryukyus
  • , Ken TakaiAffiliated withSubsurface Geobiology Advanced Research (SUGAR) Project, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
  • , Yoshihiko SakoAffiliated withLaboratory of Marine Microbiology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University
  • , Tomoo SawabeAffiliated withLaboratory of Microbiology, Faculty of Fisheries Sciences, Hokkaido University
  • , Satoshi NakagawaAffiliated withLaboratory of Microbiology, Faculty of Fisheries Sciences, Hokkaido UniversitySubsurface Geobiology Advanced Research (SUGAR) Project, Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Email author 

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Abstract

A novel heterotrophic, thermophilic bacterium, designated strain AC55T, was isolated from a deep-sea hydrothermal vent chimney at the Hatoma Knoll in the Okinawa Trough, Japan. Cells of strain AC55T were non-motile, long rods (2.0- to 6.8-μm long and 0.3- to 0.6-μm wide). The strain was an obligatory anaerobic heterotroph capable of fermentative growth on complex proteinaceous substances. Elemental sulfur was reduced to hydrogen sulfide but did not stimulate growth. Growth was observed between 37 and 60°C (optimum 55°C), pH 5.5 and 8.5 (optimum pH 6.6), and in the presence of 1.5–4.5% (w/v) NaCl (optimum 2.5%, w/v). Menaquinone-7 and -8 were the major respiratory quinones. The G + C content of the genomic DNA from strain AC55T was 51.6 mol%. The 16S rRNA gene sequence analysis revealed that strain AC55T was the first cultivated representative of Acidobacteria subdivision 10. Based on the physiological and phylogenetic features of the novel isolate, the genus name Thermotomaculum gen. nov. is proposed, with Thermotomaculum hydrothermale sp. nov. as the type species. The type strain is AC55T (=JCM 17643T = DSM 24660T = NBRC 107904T).

Keywords

Acidobacteria Deep-sea hydrothermal vent Thermophile Fermentation