Nitrincola nitratireducens sp. nov. isolated from a haloalkaline crater lake.

The novel, cream coloured, Gram-negative-staining, rod-shaped, motile bacteria, designated strains AK23T and AK28, were isolated from sediment samples collected from Lonar Lake, Buldhana district, India. The predominant fatty acids were C18:1ω7c, C16:0, C10:0 3OH and C16:1ω7c and/or iso-C15:0 2OH (summed feature 3). Polar lipid content of strains AK23T and AK28 were found to be phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphotidylserine (PS), one unidentified phospholipid (PL) and two unidentified lipids (L1 and L2). The 16S rRNA gene sequence analysis indicated strains AK23T and AK28 as the members of the genus Nitrincola and closely related to the type strain Nitrincola lacisaponensis with pair-wise sequence similarity of 97.67% and 97.62% respectively. DNA–DNA hybridization between strain AK23T and AK28 showed a relatedness of 91%. Genome of strains AK23T and N. lacisaponensis DSM 16316T were sequenced. A comparative genomics approach was used to study strains AK23T, N. lacisaponensis DSM 16316T and five other phylogenetic neighbours. The genome size of N. lacisaponensis DSM 16316T was found to be 614,784bp smaller than that of the strain AK23T. This variation could be due to multiple reasons, gene uptake, evolution, mutation, genome reduction phenomenon and draft nature of sequencing. Based on data from the current polyphasic study, strains AK23T and AK28 are proposed as novel species of the genus Nitrincola, for which the name Nitrincola nitratireducens sp. nov. is proposed. The type strain of N. nitratireducens is AK23T (=JCM 18788T=MTCC 11628T).