Paradesulfitobacterium ferrireducens gen. nov., sp. nov., a Fe(III)-reducing bacterium from petroleum-contaminated soil and reclassification of Desulfitobacterium aromaticivorans as Paradesulfitobacterium aromaticivorans comb. nov.

Abstract

A strictly anaerobic bacterium, strain PLL0T, was isolated from petroleum-contaminated soil sampled in Gansu Province, PR China. Cells were rods, non-motile and Gram-stain-positive. The strain grew at 25–37 °C (optimum, 30 °C) in the presence of 0–3 % (w/v) NaCl (optimum, 2 %). Strain PLL0T was able to reduce ferrihydrite, Fe(III) citrate and thiosulphate. The 16S rRNA gene analysis revealed that this strain clustered with the genus Desulfitobacterium , and showed highest similarity to Desulfitobacterium aromaticivorans UKTLT (95.4 %) followed by Desulfitobacterium chlororespirans Co23T (93.9 %). However, strains PLL0T and UKTLT showed no more than 94.0 % similarity to other species of the genus Desulfitobacterium , and formed an independent group in the phylogenetic tree. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between strain PLL0T and Desulfitobacterium species (except for D. aromaticivorans ) were 67.4–68.5 % and 12.6–12.7 %, respectively, which are far below the threshold for delineation of a new species. Based on ANI, dDDH, average amino acid identity, phylogenetic analysis and physiologic differences from the previously described taxa, we suggest that strain PLL0T represents a novel species of a novel genus, for which the name Paradesulfitobacterium ferrireducens gen. nov. sp. nov. is proposed. The type strain is PLL0T (=MCCC 1K05549=KCTC 25248). We also propose the reclassification of D. aromaticivorans as Paradesulfitobacterium aromaticivorans comb. nov.