Sulfurihydrogenibium yellowstonense sp. nov., an extremely thermophilic, facultatively heterotrophic, sulfur-oxidizing bacterium from Yellowstone National Park, and emended descriptions of the genus Sulfurihydrogenibium, Sulfurihydrogenibium subterraneum and Sulfurihydrogenibium azorense

Abstract

A novel thermophilic, sulfur-oxidizing Gram-negative bacterium, designated strain SS-5T, was isolated from the Calcite Hot Springs in Yellowstone National Park, USA. The cells were motile rods (1·2–2·8 μm long and 0·6–0·8 μm wide). The new isolate was a facultative heterotroph capable of using elemental sulfur or thiosulfate as an electron donor and O2 (1–18 %; optimum 6 %, v/v) as an electron acceptor. Hydrogen did not support growth. The isolate grew autotrophically with CO2. In addition, strain SS-5T utilized various organic carbon sources such as yeast extract, tryptone, sugars, amino acids and organic acids. Growth was observed between 55 and 78 °C (optimum 70 °C; 3·5 h doubling time), pH 6·0 and 8·0 (optimum pH 7·5), and 0 and 0·6 % (w/v) NaCl (optimum 0 %). The G+C content of the genomic DNA was 32 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the isolate was a member of the genus Sulfurihydrogenibium. On the basis of the physiological and molecular characteristics of the new isolate, we propose the name Sulfurihydrogenibium yellowstonense sp. nov. with SS-5T (=JCM 12773T=OCM 840T) as the type strain. In addition, emended descriptions of the genus Sulfurihydrogenibium, Sulfurihydrogenibium subterraneum and Sulfurihydrogenibium azorense are proposed.