A Gram-negative, spiral-shaped, phototrophic, purple non-sulfur bacterial strain, JA143 T , was isolated from a freshwater habitat. Strain JA143 T was motile by means of bipolar tufts of flagella. Intracellular photosynthetic membranes are of the lamellar stacked type. Bacteriochlorophyll a and carotenoids of the spirilloxanthin series with rhodovibrin are present as photosynthetic pigments. Thiamine and a reduced sulfur source are required for growth. Phylogenetic analysis on the basis of 16S

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... RNA gene sequences showed that strain JA143 T clusters with species of the genus Rhodospirillum, belonging to the class Alphaproteobacteria. The highest sequence similarities of strain JA143 T were found with the type strains of Rhodospirillum rubrum (95.6 %) and Rhodospirillum photometricum (95.7 %). Based on 16S rRNA gene sequence analysis and morphological and physiological characteristics, strain JA143 T was significantly different from the other two recognized species of the genus Rhodospirillum and represents a novel species, for which the name Rhodospirillum sulfurexigens sp. nov. is proposed. The type strain is JA143 T