Rhodobacter ovatus sp nov., a phototrophic alphaproteobacterium isolated from a polluted pond

A novel ovoid, phototrophic, purple non-sulfur bacterium was isolated in pure culture from a sample of sediment from an industrially polluted pond (Noor Mohammad Kunta) in Hyderabad, India. Strain JA234(T) was found to be Gram-negative and non-motile and grew photolheterotrophically with a number of organic compounds serving as carbon source/electron donor. Photo-organoheterotrophic and chemo-organoheterotrophic growth were demonstrated. T Biotin and thiamine were required for growth of strain JA234(T). Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain JA234(T) is most closely related to Rhodobacter azotoformans (97.3% sequence similarity) and clusters with other species of the genus Rhodobacter of the family Rhodobacteraceae. However, DNA-DNA hybridization with Rba. azotoformans JCM 9340(T) showed a relatedness of only 31.3% with respect to strain JA234(T). On the basis of 16S rRNA gene sequence analysis, DNA-DNA hybridization data and morphological and physiological characteristics, strain JA234(T) represents a novel species of the genus Rhodobacter, for which the name Rhodobacter ovatus sp. nov. is proposed. The type strain is JA234(T) (= JCM 14779(T)=CCUG 55049(T)).