Ruegeria alba sp. nov., Isolated from a Tidal Flat Sediment

A novel Gram-staining-negative, aerobic, rod-shaped, and white-colored bacterium designated as 1NDH52C^T was isolated from a tidal flat sediment and its taxonomic position was determined using a polyphasic taxonomic approach. The microorganism was found to grow at 10-37 °C, pH 6.0-9.0, and in the presence of 0-2% (w/v) NaCl, and to hydrolyze gelatin and aesculin. The major cellular fatty acid of strain 1NDH52C^T was summed feature 8 (C_19:1 ω7c and/or C_18:1 ω6c); the polar lipids comprised diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an aminolipid, and a lipid; the respiratory quinone was ubiquinone-10. The 16S rRNA gene-based phylogenetic analysis showed that strain 1NDH52C^T was closely related to members of the genus Ruegeria with the identity of 98.2% to the type strain Ruegeria pomeroyi DSM 15711^T. The genome DNA G + C content of strain 1NDH52C^T was 63.6%. The phylogenomic analysis indicated that strain 1NDH52C^T formed an independent branch distinct from reference type strains of species within this genus. Digital DNA-DNA hybridization and average nucleotide identity values between strain 1NDH52C^T and reference strains were, respectively, 19.1-41.5% and 78.3-91.3%, which are far below the thresholds of 70% and 95-96% for species definition, respectively, indicating that strain 1NDH52C^T represents a novel genospecies of the genus Ruegeria. Based on phenotypic and genotypic data, strain 1NDH52C^T is concluded to represent a novel species of the genus Ruegeria, for which the name Ruegeria alba sp. nov., is proposed. The type strain of the species is 1NDH52C^T (= GDMCC 1.2382^T = KCTC 82664^T).