| Abstract |
A Gram-staining-negative, heterotrophic, facultatively anaerobic bacterium, designated S1(T), was isolated from the Cynoglossus semilaevis culture pond in a recirculating mariculture system in Tianjin, China. The taxonomy of strain S1(T) was studied by using a polyphasic approach. Cells of strain S1(T) were non-spore-forming, curved rods, 0.4-0.6 µm wide and 1.2-2.0 µm long, and motile by means of a single polar flagellum. The strain was positive for oxidase and catalase activities. Strain S1(T) was able to grow at 4-30 °C (optimum, 25 °C), at pH 5.5-10.0 (optimum, pH 6.5-7.5) and in the presence of 1-5 % (w/v) NaCl (optimum, 2 %). Strain S1(T) contained Q-8 as the sole respiratory quinone and C16 : 1ω7c/C16 : 1ω6c and C16 : 0 as the predominant cellular fatty acids. The genomic DNA G+C content was 40.1 mol% (Tm). Phylogenetic analysis based on 16S rRNA gene sequences placed strain S1(T) in the genus Colwellia, and it formed a distinct lineage in the phylogenetic tree together with Colwellia meonggei MA1-3(T), Colwellia aestuarii SMK-10(T), Colwellia polaris 537(T) and Colwellia chukchiensis BCw111(T), with 97.7, 96.1, 95.9 and 95.0 % 16S rRNA gene sequence similarity to these strains, respectively. DNA-DNA relatedness of strain S1(T) to Colwellia meonggei MA1-3(T) was 23.5±3.6 %. On the basis of the phylogenetic and phenotypic evidence, strain S1(T) is considered to represent a novel species of the genus Colwellia, for which the name Colwellia aquaemaris sp. nov. is proposed. The type strain is S1(T) ( = CGMCC 1.12165(T) = JCM 18479(T)).
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