Colwellia polaris sp nov., a psychrotolerant bacterium isolated from Arctic sea ice

A novel psychrotolerant, Gram-negative, aerobic bacterium, designated strain 537(T), was isolated from sea-ice samples from the Arctic. Strain 537(T) was able to grow at 4-26 degrees C, with optimum growth occurring at 20-21 degrees C. Strain 537(T) had Q-8 as the major respiratory quinone and contained iso-C-15:0 2-OH and/or C-16:1 omega 7C (22.95 %), C-15:1 (17.64%) and C-17: 1 omega 8c (13.74 %) as the predominant cellular fatty acids. The genomic DNA G + C content was 38.9 mol%. A phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 537(T) formed a coherent cluster within the genus Colwellia. The highest level of 16S rRNA gene sequence similarity (97.5 %) exhibited by strain 537(T) was obtained with respect to the type strain of Colwellia aestuarii. On the basis of phenotypic, chemotaxonomic and phylogenetic properties and DNA-DNA relatedness data, strain 537(T) represents a novel species of the genus Colwellia, for which the name Colwellia polaris sp. nov. is proposed. The type strain is 537(T) (=CGMCC 1.6132(T) =JCM 13952(T)).