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

[摘要] Two strains of oval-rod shaped, Gram-negative, phototrophic, purple non-sulfur bacteria designated JA580T and JA595 were isolated from a sediment sample collected from a brown pond. Strain JA580T was designated as the type strain, while strain JA595 as an additional strain has similar characteristics to the type strain. Strain JA580T 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 JA580T requires yeast extract for growth. Strain JA580T has an obligate requirement for sulfide or thiosulfate for growth. C18:1ω7c, C18:0, C18:1ω9c were the predominant components of cellular fatty acids. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA580T 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 imhoffii (95.6%) and other members of the genus Rhodovulum (<95%). On the basis of phenotypic and molecular genetic evidence, it is proposed that strain JA580T should be classified 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 JA580T (=NBRC 107612T =KCTC 5963T).

[学科分类] 微生物学和免疫学

[关键词] Alphaproteobacteria;marine;purple non-sulfur bacterium;Rhodovulum;16S rRNA gene based phylogeny