Nautilia profundicola sp. nov., a thermophilic, sulfur-reducing epsilonproteobacterium from deep-sea hydrothermal vents

1 University of Delaware, College of Marine Studies, Lewes, DE 19958, USA 2 Delaware Biotechnology Institute, Newark, DE, USA 3 Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA 4 University of Waikato, Hamilton, New Zealand Correspondence S. Craig Cary caryc{at}udel.edu A thermophilic, strictly anaerobic, sulfur-reducing epsilonproteobacterium (strain AmH T ) isolated from deep-sea hydrothermal vents is described. Cells were motile, Gram-negative rods. Growth was observed at 30–55 °C, pH 6.0–9.0 and 2–5 % (w/v) NaCl. Chemolithoautotrophic growth occurred with molecular hydrogen or formate as the electron donor and elemental sulfur as the electron acceptor, producing hydrogen sulfide. Heterotrophic and mixotrophic growth occurred with formate as a source of carbon. The dominant phospholipid fatty acids were C 18 : 1 7 c (73.26 % of the total), C 16 : 1 7 c (12.70 %) and C 16 : 0 (12.27 %). The genomic DNA G+C content was 33.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences placed strain AmH T within the family Nautiliaceae of the Epsilonproteobacteria . DNA–DNA hybridization experiments between strain AmH T and Nautilia lithotrophica DSM 13520 T revealed a level of relatedness of 34.6 % between the two strains. Based on physiological and phylogenetic characteristics, strain AmH T is considered to represent a novel species of the genus Nautilia , for which the name Nautilia profundicola sp. nov. is proposed. The type strain is AmH T (=ATCC BAA-1463 T =DSM 18972 T ). Abbreviations: PLFA, phospholipid fatty acid; rTCA, reductive tricarboxylic acid The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain AmH T is AF357197 . Figures showing the specific growth rate of strain AmH T at varying temperatures, pH and NaCl concentrations are available as supplementary material with the online version of this paper.