Sulfuriferula nivalis sp. nov., a sulfur oxidizer isolated from snow and emended description of Sulfuriferula plumbiphila.

Abstract

A chemolithoautotrophic sulfur-oxidizing bacterium, strain SGTMT was isolated from snow collected in Japan. As electron donors for growth, SGTMT oxidized thiosulfate, tetrathionate and elemental sulfur. Heterotrophic growth was not observed. Growth of the novel isolate was observed at a temperature range of 5-28 °C, with optimum growth at 18 °C. SGTMT grew at a pH range of 4.3-7.4, with optimum growth at pH 6.1-7.1. Major components in the cellular fatty acid profile were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The complete genome of SGTMT consisted of a circular chromosome of approximately 3.4 Mbp and two plasmids. Phylogenetic analysis based on the 16S rRNA gene indicated that SGTMT represented a member of the genus Sulfuriferula, and its closest relative is Sulfuriferula thiophila mst6T with a sequence identity of 98 %. A comparative genome analysis showed dissimilarity between the genomes of SGTMT and S. thiophila mst6T, as low values of average nucleotide identity (74.9 %) and digital DNA-DNA hybridization (20.4%). On the basis of its genomic and phenotypic properties, SGTMT (=DSM 109609T=BCRC 81185T) is proposed as the type strain of a novel species, Sulfuriferula nivalis sp. nov. Some characteristics of another species in the same genus, Sulfuriferula plumbiphila, were also investigated to revise and supplement its description. The type strain of S. plumbiphila can grow on thiosulfate, tetrathionate and elemental sulfur. The strain showed optimum growth at pH 6.3-7.0 and shared major cellular fatty acids with the other species of the genus Sulfuriferula.