Desulfurispirillum indicum sp. nov., a selenate- and selenite-respiring bacterium isolated from an estuarine canal

Strain S5(T), a novel bacterium that was isolated for its capability to respire selenate to elemental selenium, is described. In addition to selenate respiration, it was also capable of dissimilatory selenite, arsenate and nitrate reduction with short-chain organic acids such as pyruvate, lactate and acetate as the carbon sources and electron donors. The isolate was unable to grow fermentatively. Strain S5(T) was isolated from sediment of an estuarine canal in Chennai, India. Phylogenetic analysis of the 16S rRNA gene of this novel isolate revealed that it belonged to the family Chrysiogenaceae with sequence similarities of 92 and 98%, respectively, with the type strains of Chrysiogenes arsenatis and Desulfurispirillum alkaliphilum, its closest known relatives. Strain S5(T) and D. alkaliphilum were closely related in terms of their 16S rRNA gene phylogeny; however, they varied greatly in their genomic DNA G + C content (56 mol% versus 45 mol%) and cellular fatty acid compositions, as well as in many metabolic capabilities. Strain S5(T) represents a novel species for which the name Desulfurispirillum indicum sp. nov. is proposed; the type strain is S5(T) (=DSM 22839(T) =ATCC BAA-1389(T)).