Polaribacter aquimarinus sp. nov., isolated from the surface of a marine red alga.

A Gram-stain negative, non-motile, asporogenous, aerobic and rod-shaped bacterial strain, designated ZY113T, was isolated from the surface of a marine red alga collected from the coast in Weihai, Shandong Province, China. Strain ZY113T was found to grow at 4-37 °C (optimum at 28-30 °C), with 1.0-7.0% (w/v) NaCl (optimum 2.0-3.0%) and at pH 6.0-9.0 (optimum 7.0-8.0). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain ZY113T is a member of the genus Polaribacter, with Polaribacter dokdonensis KCTC 12392T as a close relative (97.4% similarity). The sole respiratory quinone was found to be menaquinone 6 (MK-6) and the major fatty acids were identified as iso-C15:0, iso-C15:0 3-OH and iso-C13:0. The polar lipids were found to consist of phosphatidylethanolamine, two unidentified aminolipids and three unidentified lipids. The G + C content of the genomic DNA was determined to be 30.1 mol%. On the basis of phenotypic, genotypic and phylogenetic analysis, strain ZY113T is considered to represent a novel species of the genus Polaribacter, for which the name Polaribacter aquimarinus sp. nov. is proposed. The type strain is ZY113T (= KCTC 62374T = MCCC 1H00296T).