Hahella antarctica sp. nov., isolated from Antarctic seawater.

A Gram-negative, psychrotolerant, chemoheterotrophic, aerobic, cream-coloured bacterium, designated IMCC3113(T), was isolated from coastal seawater from the Antarctic. On the basis of 16S rRNA gene sequence similarity analyses, the strain was most closely related to the type strains of Hahella chejuensis (93.0 %) and Hahella ganghwensis (92.1 %) in the Gammaproteobacteria. Phylogenetic investigations using 16S rRNA gene sequences showed that this Antarctic marine isolate formed a robust monophyletic clade with the two Hahella species but constituted a distinct phyletic line in the clade. The DNA G+C content of strain IMCC3113(T) was 56.4 mol% and the major respiratory quinone was Q-9. Several phenotypic and physiological characteristics, including the temperature range and NaCl optimum for growth, several enzyme activities and the cellular fatty acid composition, served to differentiate the strain from the two Hahella species. Therefore strain IMCC3113(T) represents a novel species of the genus Hahella, for which the name Hahella antarctica sp. nov. is proposed. The type strain is IMCC3113(T) (=KCCM 42675(T) =NBRC 102683(T)).