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 degrees C (optimum, 20 degrees 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 C-16:0 (10.7%), C-18:0 (9.2%), C-16:1 omega 5c (16.5 %) and summed feature 3 (C-16:1 omega 6c and/or C-16:1 omega 7c) (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)).