Polaribacter marinaquae sp. nov., isolated from seawater.

A novel Gram-stain-negative, rod-shaped, non-spore-forming, non-flagellated, strictly aerobic strain, designated RZW3-2T, was isolated from seawater from near the Yellow Sea coast of PR China (35.475° N 119.613° E). The organism grew optimally between 24 and 28 °C, at pH 6.0-7.0 and in the presence of 2-3 % (w/v) NaCl. The strain requires seawater or artificial seawater for growth and NaCl alone does not support growth. RZW3-2T contained iso-C15 : 0, C16 : 1ω7c and/or C16 : 1ω6c and anteiso-C15 : 0 as the dominant fatty acids. The respiratory quinone detected in RZW3-2T was menaquinone 6 (MK6). The polar lipids of RZW3-2T comprised phosphatidylethanolamine (PE), four unidentified phospholipids (PL), two unidentified aminolipids (AL) and one unknown lipid (L). The DNA G+C content of RZW3-2T was 30.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel strain was related most closely to Polaribacter reichenbachii KCTC 23969T, Polaribacter dokdonensis KCTC 12392T and Polaribacter irgensii CIP 106478T with 98.0, 97.8 and 97.0 % sequence similarities, respectively. The DNA-DNA hybridization values between RZW3-2T and its closest phylogenetic relatives, P. reichenbachii KCTC 23969T and P. dokdonensis KCTC 12392T, were 52.0±0.6 % and 49.8±1.21 % respectively. On the basis of polyphasic analyses, RZW3-2T represents a novel species of the genus Polaribacter, for which the name Polaribacter marinaquae sp. nov. is proposed. The type strain is RZW3-2T (=JCM 30825T=KCTC 42664T=MCCC 1K00696T).