Rhodovulum phaeolacus sp. nov. a phototrophic alphaproteobacterium isolated from a brown pond

Abstract

Two strains of oval-rod shaped, Gram-negative, phototrophic, purple non-sulfur bacteria designated JA580 T and JA595 were isolated from a sediment sample collected from a brown pond. Strain JA580 T was designated as the type strain, while strain JA595 as an additional strain has similar characteristics to the type strain. Strain JA580 T was non-motile and grew photoheterotrophically with a number of organic compounds serving as carbon source/electron donor. Intracellular photosynthetic membranes were of the vesicular type. Bacteriochlorophyll a and carotenoids of the spheroidene series were present as the major photosynthetic pigments. Strain JA580 T requires yeast extract for growth. Strain JA580T has an obligate requirement for sulfi de or thiosulfate for growth. C 18:1ω7c, C 18:0, C 18:1ω9c were the predominant components of cellular fatty acids. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA580 T clustered with species of the genus Rhodovulum of the family Rhodobacteraceae and is most closely related to the type strains of Rhodovulum adriaticum, Rhodovulum iodosum (96.5%), Rhodovulum robiginosum (96%), Rhodovulum imhoffi i (95.6%) and other members of the genus Rhodovulum (<95%). On the basis of phenotypic and molecular genetic evidence, it is proposed that strain JA580 T should be classifi ed as a novel species of the genus Rhodovulum of the family Rhodobacteraceae, with the species name Rhodovulum phaeolacus sp. nov. The type strain of the species is JA580 T (=NBRC 107612 T =KCTC 5963 T).