Shewanella seohaensis sp. nov., isolated from a tidal flat sediment

A Gram-negative, motile and rod-shaped bacterial strain, designated S7-3(T), was isolated from a tidal flat sediment at Saemankum on the western coast of Korea. Phylogenetic analyses based on 16S rRNA gene and gyrB sequences showed that strain S7-3(T) belonged to the genus Shewanella, clustering with Shewanella decolorationis S12(T). Strain S7-3(T) exhibited 98.8 % 16S rRNA gene sequence similarity and 96.8 % gyrB sequence similarity to S. decolorationis S12(T), respectively. The 16S rRNA gene sequence similarity values between strain S7-3(T) and other members of the genus Shewanella were in the range of 93.0-98.0 %. Strain S7-3(T) contained simultaneously both menaquinones (MK) and ubiquinones (Q); the predominant menaquinone was MK-7 and the predominant ubiquinones were Q-7 and Q-8. The fatty acid profiles of strain S7-3(T) and S. decolorationis JCM 21555(T) were similar; major components were C(17:1) ω8c, iso-C(15:0) and iso-C(15:0) 2-OH and/or C(16:1) ω7c. The DNA G+C content of strain S7-3(T) was 51.8 mol% and its mean DNA-DNA relatedness value with S. decolorationis JCM 21555(T) was 43 %. Differential phenotypic properties of strain S7-3(T), together with the phylogenetic and genetic distinctiveness, revealed that this strain is distinguishable from recognized Shewanella species. On the basis of the data presented, strain S7-3(T) is considered to represent a novel Shewanella species, for which the name Shewanella seohaensis sp. nov. is proposed. The type strain is S7-3(T) (=KCTC 23556(T) = CCUG 60900(T)).