Thauera propionica sp. nov., isolated from downstream sediment sample of the river Ganges, Kanpur, India.

A Gram-stain-negative, non-endospore-producing, short-rod strain, KNDSS-Mac4, was isolated from a downstream sediment sample of the river Ganges, Kanpur, India and studied by using the polyphasic taxonomic approach. 16S rRNA gene sequence analysis uncovered that the strain had similarity to species of the genus Thauera and formed a distinct phylogenetic cluster with Thauera humireducens KACC16524. However, KNDSS-Mac4 showed closest phylogenetic affiliation to Thauera aminoaromatica DSM 14742 with 16S rRNA gene sequence similarity of 98.7 % followed by Thauera phenylacetica DSM 14743 (98.6 %), Thauera chlorobenzoica (98.2 %), T. humireducens KACC16524 (98.2 %), Thauera selenatis ATCC 55363 (98.2 %) and Thauera mechernichensis DSM 12266 (98.0 %). The digital DNA-DNA hybridization and average nucleotide identity values between strain KNDSS-Mac4 and the two most closely related taxa, T. aminoaromatica DSM 14742 and T. phenylacetica DSM 14743, were 26.0, 26.7 and 84.0, 84.3 % respectively. Major lipids present were phosphatidylglycerol, three unknown aminophospholipids, phosphatidylmethylethanolamine, two unidentified lipids and Q-8 as the only ubiquonone. The major cellular fatty acids present were C16 : 1 ω6c/C16 : 1ω7c and C16 : 0. The DNA G+C content of strain KNDSS-Mac4 was 65.9 %. Based on data from phenotypic tests and the genotypic differences of strain KNDSS-Mac4 from its closest phylogenetic relatives, it is evident that this isolate should be regarded as a new species. It is proposed that strain KNDSS-Mac4 should be classified in the genus Thauera as a novel species, Thauerapropionica sp. nov. The type strain is KNDSS-Mac4 (=KCTC 52820=VTCC-B-910017).