gen. nov., sp. nov., a facultatively anaerobic bacterium isolated from Yongle Blue Hole in the South China Sea.

Blue holes are unique geomorphological units characterized by steep redox and biogeochemical gradients. Yongle Blue Hole is located on the largest atoll (Yongle Atoll) of the western Xisha Islands in the South China Sea. A Gram-stain-negative, facultatively anaerobic, non-motile, non-flagellated marine bacterium with creamy white colonies, designated JC036, was isolated from Yongle Blue Hole. Cells were short-rod-shaped and catalase-negative. 16S rRNA gene sequence analysis showed that sequence similarities were lower than 91.6 % against all validly named species in the family ; a reconstructed phylogenetic tree indicated that strain JC036 formed a lineage with strains in the family . Growth occurred at 4-37 °C (optimum, 28 °C), at pH 5.0-9.0 (optimum, 7.0) and in the presence of 2-6 % (w/v) NaCl (optimum, 3 %). The prevalent isoprenoid quinone of strain JC036 was menaquinone-7 (MK-7). Iso-C and iso-C 3-OH were the predominant fatty acids. The major polar lipids included a phospholipid, phosphatidylethanolamine, an aminophospholipid and four unidentified lipids. The genomic DNA G+C content of strain JC036 was 37.8 mol%. Based on physiological and biochemical characteristics and whole genome comparisons, we propose a new genus and species, gen. nov., sp. nov., within the family . The type strain of is JC036 (=JCM 33128=MCCC 1K03579). From this study, a deeper understanding of the community of the microorganism and their roles in biogeochemical cycles, especially anaerobic bacteria, is provided.