Spirosoma arcticum sp. nov., isolated from high Arctic glacial till

A novel orange-pigmented strain, designated R2-35(T), was isolated from a glacier till near Ny-Alesund, Svalbard Archipelago, Norway. The cells were aerobic, Gram-negative, rod-shaped and sometimes filamentous. Growth occurred at 4-28 °C (optimum, 20 °C), at pH 7.0-9.0 (optimum, pH 8.0) and with 0-1% NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain R2-35(T) belonged to the genus Spirosoma with sequence similarity to related species ranging from 91.65 to 95.19%. Strain R2-35(T) contained C16 : 0 (10.7%), C18 : 0 (9.2%), C16 : 1ω5c (16.5%) and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) (24.6%) as the major cellular fatty acids, MK-7 as the major respiratory quinone, and phosphatidylethanolamine as the main polar lipid. The DNA G+C content of strain R2-35(T) was 54.9 mol%. On the basis of phylogenetic, physiological and chemotaxonomic data, strain R2-35(T) is considered to represent a novel species of the genus Spirosoma, for which the name Spirosoma arcticum sp. nov., is proposed, The type strain is R2-35(T) ( = CCTCC AB 2012849(T) = LMG 28141(T)).