Thermococcus henrietii sp. nov., a novel extreme thermophilic and piezophilic sulfur-reducing archaeon isolated from a deep-sea hydrothermal chimney

A novel extreme thermophilic and piezophilic chemoorganoheterotrophic archaeon, strain EXT12c T , was isolated from a hydrothermal chimney sample collected at depth of 2496 m the East Pacific Rise 9° N. Cells were strictly anaerobic, motile cocci. The grew NaCl concentrations ranging 1 to 5 % (w/v; optimum, 2.0%), pH 6.0 7.5 (optimum, 6.5–7.0), temperatures between 60 95 °C 80–85 °C), pressures 0.1 least 50 MPa 30 MPa). Strain chemoorganoheterotrophically on complex proteinaceous substrates. Its growth highly stimulated by presence elemental sulphur or l -cystine, which reduced hydrogen sulfide. DNA G+C content 54.58 mol%. Phylogenetic analyses based 16S rRNA gene sequences concatenated ribosomal protein showed that falls into genus Thermococcus is most closely related nautili 30-1 . Overall genome relatedness index (average nucleotide identity scores in silico DNA–DNA hybridizations) sufficient genomic distance new ones type strains for delineation species. On basis genotypic phenotypic data, considered represent species, name henrietii sp. nov. proposed, with (=UBOCC M-2417 =DSM 111004 ).