Rhodovulum aestuarii sp. nov., isolated from a brackish water body

Abstract

A yellowish brown, phototrophic, purple non-sulfur bacterium, strain JA924T, was isolated in pure culture from a brackish water sample collected from an estuary. Single cells were oval to rod-shaped, non-motile and Gram-stain-negative and had a vesicular architecture of intracellular photosynthetic membranes. Bacteriochlorophyll-a and carotenoids of the spheroidene series were present as photosynthetic pigments. Photolithoautotrophy, chemo-organoheterotrophy and photo-organoheterotrophy were the growth modes observed. Strain JA924T had complex growth requirements. Strain JA924T was mesophilic and moderately halophilic. The DNA G+C content was 64 mol% (HPLC). The major cellular fatty acids were C18:1ω7c/C18:1ω6c, C16:0 and C18:0. The major quinone was ubiquinone-10 (Q-10). Phosphatidylglycerol, phosphatidylethanolamine, sulfolipid and an aminolipid were the main polar lipids of strain JA924T. EzTaxon-e blast searches based on the 16S rRNA gene sequence of JA924T revealed highest similarity with Rhodovulum mangrovi AK41T (98.19 %) and other members of the genus Rhodovulum ( < 95.71 %). Strain JA924T was further identified to be distantly related to Rhodovulum mangrovi AK41T ( < 29 % based on DNA–DNA hybridization and ΔTm ( > 5 °C). Phenotypic, chemotaxonomic and molecular differences indicate that strain JA924T represents a novel species of the genus Rhodovulum, for which the name Rhodovulum aestuarii sp. nov. is proposed. The type strain is JA924T (=LMG 29031T=KCTC 15485T).