Exiguobacterium aestuarii sp nov and Exiguobacterium marinum sp nov., isolated from a tidal flat of the Yellow Sea in Korea

Three Gram-variable, rod-shaped bacterial strains, TF-16(T), TF- 19 and TF-80(T), were isolated from a tidal flat of Daepo Beach (Yellow Sea) near Mokpo City, Korea, and their taxonomic positions were investigated by a polyphasic approach. These isolates grew optimally in the presence of 2% NaCl and at 30 degrees C. Their pepticloglycan types were based on L-Lys-Gly. The predominant menaquinone detected in the three strains was MK-7. The three strains contained large amounts of the branched fatty acids iso-C-17:0, anteiso-C-13:0, iso-C-13:0 and iso-C-15:0. The DNA G+C contents of strains TF-16(T), TF-19 and TF-80(T) were 48.6, 48.4 and 48.0 mol%, respectively. The three strains formed a coherent cluster with Exiguobacterium species in a phylogenetic tree based on 16S rRNA gene sequences. They showed closest phylogenetic affiliation to Exiguobacterium aurantiacum, with 16S rRNA gene sequence similarity values of 98.1-98.3%. The three strains exhibited 16S rRNA gene sequence similarity values of 94-0-94-6% to the type strains of other Exiguobacterium species. Levels of DNA-DNA relatedness indicated that strains TF-16(T) and TF-19 and strain TF-80(T) are members of two species that are separate from E aurantiacum. On the basis of phenotypic, phylogenetic and genetic data, strains TF-16(T) and TF-19 and strain TF-80(T) represent two novel species in the genus Exiguobacterium; the names Exiguobacterium aestuarii sp. nov. (type strain TF-16(T) = KCTC 19035(T) = DSM 16306(T); reference strain TF-19) and Exiguobacterium marinum sp. nov. (type strain TF-80(T) = KCTC 19036(T) = DSM 16307(T)) are proposed.