Aquipluma nitroreducens gen. nov. sp. nov., a novel facultatively anaerobic bacterium isolated from a freshwater lake.

ABSTRACT

A novel facultatively anaerobic, nitrate-reducing bacterium, designated MeG22T, was isolated from a freshwater lake in Japan. Cells of the strain were straight rods (0.8×2.5-10 µm), motile, and Gram-stain-negative. For growth, the optimum NaCl concentration was 0 % and the optimum temperature was 30 °C. Under anoxic conditions, strain MeG22T reduced nitrate to nitrite. Major cellular fatty acids were C15  1 ω6c (13.6 %), C17  0 (11.9 %), anteiso-C15  0 (10.6 %) and iso-C15  0 (10.6 %). The major respiratory quinone was menaquinone-7. The genome sequence of strain MeG22T consists of 5 712 279 bp with a G+C content of 40.3 mol%. Phylogenetic analysis based on the 16S rRNA gene revealed that the novel strain belonged to the family Prolixibacteraceae within the phylum Bacteroidetes. The closest relative of strain MeG22T was Sunxiuqinia faeciviva strain JAM-BA0302T with a 16S rRNA gene sequence similarity of 90.9 %. On the basis of phylogenetic and phenotypic characterization, Aquipluma nitroreducens, gen. nov., sp. nov., belonging to the family Prolixibacteraceae is proposed with the type strain MeG22T (=NBRC 112896T=DSM 106262T).