Polaribacter sejongensis sp. nov., isolated from Antarctic soil, and emended descriptions of the genus Polaribacter , Polaribacter butkevichii and Polaribacter irgensii

Abstract

A Gram-staining-negative, catalase- and oxidase-positive, non-motile bacterium, designated strain KOPRI 21160T, was isolated from Antarctic soil. Based on 16S rRNA gene sequence analysis, strain KOPRI 21160T was found to belong to the genus Polaribacter . Sequence similarity between strain KOPRI 21160T and the type strains of species of the genus Polaribacter was 94.2–98.3 %. The nearest phylogenetic neighbours of strain KOPRI 21160T were Polaribacter butkevichii KCTC 12100T (98.3 % similarity) and Polaribacter irgensii KCTC 23136T (97.5 %). DNA–DNA relatedness was 50.6 %, between strain KOPRI 21160T and P. butkevichii KCTC 12100T, and 45.2 % between strain KOPRI 21160T and P. irgensii KCTC 23136T. Strain KOPRI 21160T grew at 4–37 °C and at pH 7.0–8.5. It could hydrolyse DNA, starch and Tweens 20, 40, 60 and 80. Menaquinone-6 (MK-6) was the only respiratory quinone, and iso-C15 : 0, iso-C15 : 0 3-OH and C15 : 1ω6c were the major cellular fatty acids. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids and one unidentified lipid. The DNA G+C content was 30.0 mol%. Based on data from our polyphasic study, the organism is considered to represent a novel species of the genus Polaribacter , for which we propose the name Polaribacter sejongensis sp. nov. The type strain is KOPRI 21160T ( = KCTC 23670T = JCM 18092T). Emended descriptions of the genus Polaribacter , Polaribacter butkevichii Nedashkovskaya et al. 2005 and Polaribacter irgensii Gosink et al. 1998 are also proposed.