Cyclobacterium sediminis sp. nov. isolated from a sea cucumber aquaculture farm and emended description of the genus Cyclobacterium.

An aerobic, Gram-negative bacterium, designated strain SD70(T), was isolated from sea cucumber aquaculture farm sediment in Taean, Korea, and its taxonomic status was established by undertaking a polyphasic study. Cells of strain SD70(T) were non-motile, catalase-, and oxidase-positive, non-spore-forming, and horseshoe-shaped. Optimal growth was observed under 25-30°C, pH 7.0-8.0, and 3.0-5.0% (w/v) NaCl conditions. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain SD70(T) fell within an evolutionary group comprising species of the genus Cyclobacterium. Strain SD70(T) shared 92.1-98.5% 16S rRNA sequence similarity values with the type strains of species of the genus Cyclobacterium. Relatively low levels of DNA-DNA relatedness were found between strain SD70(T) and C. marinum DSM 745(T) (40.2%) and C. amurskyense KMM 6143(T) (15.8%). The predominant cellular fatty acids were iso-C15:0 (32.1%), and anteiso-C15:0 (9.1%). Menaquinone MK-7 was the only respiratory quinone. The G+C content of the genomic DNA was 36 mol%. The polar lipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and seven unidentified lipids. On the basis of phenotypic and genotypic data, strain SD70(T) represents a novel species of the genus Cyclobacterium, for which the name Cyclobacterium sediminis sp. nov. is proposed. An emended description of the genus Cyclobacterium is also provided.