Paralabilibaculum antarcticum gen. nov., sp. nov., an anaerobic marine bacterium of the family Marinifilaceae isolated from Antarctica sea ice.

A novel bacterial strain, designated DW002, was isolated from the sea ice of Cape Evans, McMurdo Sound, Antarctica. Cells of the strain were Gram-negative, obligate anaerobic, motile, non-flagellated, and short rod-shaped. The strain DW002 grew at 4-32 ℃ (optimum at 22-28 ℃) and thrived best at pH 7.0, NaCl concentration of 2.5% (w/v). The predominant isoprenoid quinone of strain DW002 was menaquinone-7 (MK-7). The major fatty acids (> 10%) of DW002 were iso-C, anteiso-C and iso-Cω9c. The predominant polar lipids of strain DW002 contained two phosphatidylethanolamines, one unidentified glycolipid, one unidentified aminolipid and four unidentified lipids. The DNA G + C content of the strain DW002 was 34.8%. Strain DW002 encoded 237 carbohydrate-active enzymes. The strain DW002 had genes associated with dissimilatory nitrate reduction and assimilatory sulfate reduction metabolic pathways. Based on distinct physiological, chemotaxonomic, genome analysis and phylogenetic differences compared to other members of the phylogenetically related genera in the family Marinifilaceae, strain DW002 is proposed to represent a novel genus within the family. Therefore, the name Paralabilibaculum antarcticum gen. nov., sp. nov. is proposed. The type strain is DW002 (=KCTC 25274=MCCC 1K06067).