Rheinheimera aestuari sp. nov., a marine bacterium isolated from coastal sediment

Abstract

A Gram-stain-negative, strictly aerobic, non-pigmented, motile bacterium with a single polar flagellum, designated H29T, was isolated from coastal sediment of Jeju Island, South Korea. Cells were non-spore-forming rods showing catalase- and oxidase-positive reactions. Growth of strain H29T was observed at 10–40 °C (optimum, 20–25 °C) and pH 6.0–9.0 (optimum, pH 7.0–8.0), and in the presence of 1–4 % (w/v) NaCl (optimum, 2–3 %). Strain H29T contained C16 : 0, iso-C15 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c) as the major fatty acids and ubiquinone-8 (Q-8) as the sole isoprenoid quinone. Phosphatidylethanolamine and phosphatidylglycerol were identified as the major polar lipids. The G+C content of the genomic DNA was 46.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain H29T formed a phyletic lineage with Rheinheimera hassiensis E48T within the genus Rheinheimera of the family Chromatiaceae. Strain H29T was most closely related to Rheinheimera pacifica KMM 1406T, Rheinheimera muenzenbergensis E49T, Rheinheimera hassiensis E48T and Rheinheimera baltica OSBAC1T with 97.8 %, 97.6 %, 97.4 % and 97.2 % 16S rRNA gene sequence similarities, respectively. However, DNA–DNA hybridization values of strain H29T with type strains of these species were lower than 70 %. On the basis of the phenotypic, chemotaxonomic and molecular properties, strain H29T represents a novel species of the genus Rheinheimera, for which the name Rheinheimera aestuarii sp. nov. is proposed. The type strain is H29T ( = KACC 18251T = JCM 30404T).