Aquimarina gracilis sp. nov., isolated from the gut microflora of a mussel, Mytilus coruscus, and emended description of Aquimarina spongiae.

An orange-coloured and slender rod-shaped bacterium, designated strain PSC32(T), was isolated from the gut microflora of a mussel collected from Gwangyang Bay, South Sea (Republic of Korea). Cells were Gram-reaction-negative, strictly aerobic, and catalase- and oxidase-positive. The major fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, iso-C15 : 1 G and iso-C15 : 0 3-OH. The only isoprenoid quinone of strain PSC32(T) was MK-6 and the DNA G+C content was 36.9 mol%. Phosphatidylethanolamine, one unidentified aminolipid and two unidentified polar lipids were found as major polar lipids. A phylogenetic tree based on 16S rRNA gene sequences showed that strain PSC32(T) forms an evolutionary lineage within the genus Aquimarina and is closely related to Aquimarina spongiae A6(T) (97.0 % similarity) and to other members of the genus Aquimarina (94.4-96.5 %). Genomic DNA-DNA relatedness between strain PSC32(T) and A. spongiae A6(T) was 40.7 %. A number of phenotypic characteristics distinguished strain PSC32(T) from described members of the genus Aquimarina. On the basis of the evidence presented in this study, strain PSC32(T) represents a novel species, for which the name Aquimarina gracilis sp. nov. is proposed. The type strain is PSC32(T) ( = KCTC 23301(T) = JCM 17453(T)). An emended description of Aquimarina spongiae is given.