Shewanella marisflavi sp. nov. and Shewanella aquimarina sp. nov., slightly halophilic organisms isolated from sea water of the Yellow Sea in Korea

Abstract

Two Gram-negative, motile, non-spore-forming, rod-shaped organisms, strains SW-117T and SW-120T, were isolated from sea water of the Yellow Sea in Korea and subjected to a polyphasic taxonomic study. Strains SW-117T and SW-120T simultaneously contained both menaquinones (MK) and ubiquinones (Q) as isoprenoid quinones; the predominant menaquinone was MK-7 and the predominant ubiquinones were Q-7 and Q-8. The major fatty acid detected in the two strains was iso-C15:0. The DNA G + C content of strains SW-117T and SW-120T was 51 and 54 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-117T and SW-120T fall within the radiation of the cluster comprising Shewanella species. Strains SW-117T and SW-120T showed a 16S rRNA gene sequence similarity of 97.4% and a DNA-DNA relatedness level of 10.1%. Strains SW-117T and SW-120T exhibited 16S rRNA gene sequence similarity levels of 93.8-98.5% and 92.4-97.0%, respectively, to Shewanella species. Strain SW-117T exhibited DNA-DNA relatedness levels of 8.3-20.3% to the type strains of six phylogenetically related Shewanella species. On the basis of phenotypic, phylogenetic and genetic data, strains SW-117T and SW-120T were classified in the genus Shewanella as two distinct novel species, for which the names Shewanella marisflavi sp. nov. (type strain, SW-117T=KCCM 41822T=JCM 12192T) and Shewanella aquimarina sp. nov. (type strain, SW-120T=KCCM 4182T=JCM 12193T) are proposed, respectively.