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

Abstract

A Gram-staining-negative, aerobic, non-flagellated, non-gliding and ring-like or horseshoe-shaped 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(16:1)ω6c 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(T) were 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.