Cyclobacterium caenipelagi sp. nov., isolated from a tidal flat sediment, and emended description of the genus Cyclobacterium

A Gram-staining-negative, aerobic, non-flagellated, non-gliding and ring-like or horseshoeshaped bacterial strain, designated HD-17^T, was isolated from a tidal flat sediment in the Korean peninsula. Strain HD-17^T grew optimally at pH 7.0-8.0, at 25 °C and in the presence of 2.0% (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain HD- 17^T fell within the clade comprising species of the genus Cyclobacterium. Strain HD-17^T exhibited 16S rRNA gene sequence similarity values of 93.8-98.8% to the type strains of species of the genus Cyclobacterium. Strain HD-17^T contained MK-7 as the predominant menaquinone and iso-C_15:0, summed feature 3 (C_16:1ω6c and/or C_16:1 ω7c), anteiso-C_15:0 and iso-C_15:1 G as the major fatty acids. The major polar lipids of strain HD-17^T were phosphatidylcholine, phosphatidylethanolamine and two unidentified lipids. The DNA G + C content of strain HD-17^T was 43.8 mol% and its DNA-DNA relatedness values with Cyclobacterium amurskyense KCTC 12363^T, Cyclobacterium qasimii KCTC 23011^T and Cyclobacterium marinum KCTC 2917^Twere 10.4, 7.6 and 5.3%, respectively. The phylogenetic and genetic distinctiveness and several differentiating phenotypic properties revealed that strain HD-17^T was separate from other species of the genus Cyclobacterium. On the basis of the data presented, strain HD-17^T represents a novel species of the genus Cyclobacterium, for which the name Cyclobacterium caenipelagi sp. nov. is proposed. The type strain is HD-17^T (=KCTC 32178^T=CCUG 63247^T). An emended description of the genus Cyclobacterium is also provided.