Mariniflexile jejuense sp. nov., isolated from the junction between seawater and a freshwater spring, and emended description of the genus Mariniflexile

Abstract

A Gram-negative, non-spore-forming, non-flagellated, motile-by-gliding rod, designated SSK2-3T, was isolated from the junction between seawater and a freshwater spring at Jeju island, South Korea. Strain SSK2-3T grew optimally at 25-30 °C, at pH 7.0-7.5 and in the presence of 2% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SSK2-3T clustered with type strains of species of the genus Mariniflexile, with which it exhibited 97.2-97.8% 16S rRNA gene sequence similarity. Sequence similarity between the isolate and the other strains used in the phylogenetic analysis was <95.6%. Strain SSK2-3T contained MK-6 as the predominant menaquinone and iso-C15:0, iso-C15:1 G and C15:0 as the major fatty acids. The major polar lipids of strain SSK2-3T were phosphatidylethanolamine and one unidentified lipid. The DNA G+C content of strain SSK2-3T was 32.4 mol%. DNA-DNA relatedness between the isolate and Mariniflexile gromovii KCTC 12570T, Mariniflexile fucanivorans DSM 18792T and Mariniflexile aquimaris HWR-17T was 19, 15 and 20%, respectively. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain SSK2-3T is separate from other members of the genus Mariniflexile. On the basis of the data presented, strain SSK2-3T is considered to represent a novel species of the genus Mariniflexile, for which the name Mariniflexile jejuense sp. nov. is proposed. The type strain is SSK2-3T (=KCTC 23958T =CCUG 62414T). An emended description of the genus Mariniflexile is given.