Sunxiuqinia faeciviva sp nov., a facultatively anaerobic organoheterotroph of the Bacteroidetes isolated from deep subseafloor sediment

A facultatively anaerobic organoheterotroph, designated JAM-BA0302(T), was isolated from a deep subseafloor sediment at a depth of 247.1 m below the seafloor off the Shimokita Peninsula of Japan in the north-western Pacific Ocean (Site 09001, water depth 1180 m). Cells of strain JAM-BA0302(T) showed gliding motility and were thin, long rods with peritrichous fimbriae-like structures. Growth occurred at 4-37 degrees C (optimum 30 degrees C; doubling time 8 h), at pH 5.4-8.3 (optimum pH 7.5) and with 5-60 g NaCl l(-1) (optimum 20-25 g l(-1)). The isolate utilized proteinaceous substrates such as yeast extract, tryptone, casein and Casamino acids with O-2 respiration or fermentation. Strain JAM-BA0302(T) was a piezotolerant bacterium that could grow at pressures as high as 25 MPa under aerobic conditions and 10 MPa under anaerobic conditions. The G+C content of the genomic DNA was 43.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JAM-BA0302(T) was most closely related to yet-undescribed strains recently isolated from various marine sedimentary environments (>99.6% 16S rRNA gene sequence similarity) and was moderately related to Sunxiuqinia elliptica DOHS-4(T), isolated from a sea cucumber farm sediment (95.5% 16S rRNA gene sequence similarity) within the Bacteroidetes. The phylogenetic analysis suggested that the isolate should belong to the genus Sunxiuqinia. However, low DNA-DNA relatedness (<11%) and many physiological and molecular properties differentiated the isolate from those previously described. We propose here a novel species of the genus Sunxiuqinia, with the name Sunxiuqinia faeciviva sp. nov. The type strain is JAM-BA0302(T) (=JCM 15547(T) =NCIMB 14481(T)).