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

A novel facultatively anaerobic, nitrate-reducing bacterium, designated MeG22(T), was isolated from a freshwater lake in Japan. Cells of the strain were straight rods (0.8x2.5-10 mu m), motile, and Gram-stain-negative. For growth, the optimum NaCl concentration was 0% and the optimum temperature was 30 degrees C. Under anoxic conditions, strain MeG22(T) reduced nitrate to nitrite. Major cellular fatty acids were C-15:1 omega 6c (13.6 %), C-17:0 (11.9 %), anteiso-C-15:0 (10.6 %) and iso-C-15:0 (10.6 %). The major respiratory quinone was menaquinone-7. The genome sequence of strain MeG22(T) consists of 5 712 279 bp with a G+C content of 40.3mol%. 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 MeG22(T) was Sunxiuqinia faeciviva strain JAM-BA0302(T) 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 MeG22(T) (=NBRC 112896(T)=DSM 106262(T)).