Sphingosinithalassobacter tenebrarum sp. nov., isolated from a deep-sea cold seep.

A Gram-stain-negative, facultatively anaerobic, yellow-pigmented, non-motile, rod-shaped bacterium, designated zrk23^T, was isolated from a deep-sea cold seep. The strain was characterized by a polyphasic approach to clarify its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequences placed zrk23^T within the genus Sphingosinithalassobacter and showed the highest similarity to Sphingosinithalassobacter portus FM6^T (97.93 %). Growth occurs at temperatures from 16 to 45 °C (optimum, 30 °C), at pH values between pH 6.0 and 8.5 (optimum, pH 7.0) and in 0-5.0 % (w/v) NaCl (optimum, 1.5 %). The major fatty acids were C_16 : 0, C_14 : 0 2-OH and summed feature 8 (C_18 : 1ω7c and/or C_18 : 1ω6c). The major isoprenoid quinone was ubiquinone-10. Predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol, one unidentified phosphoglycolipid, three unidentified glycolipids and three unidentified phospholipids. The G+C content of the genomic DNA was 64.69 %. The average nucleotide identity values between zrk23^T and the most closely related available genome, of Sphingosinithalassobacter portus FM6^T, was 82.21 %, indicating that zrk23^T was clearly distinguished from S. portus. The analysis of genome sequence of zrk23^T revealed that there were many genes associated with degradation of aromatic compounds existing in the genome of zrk23^T. As a result of the combination of the results of phylogenetic analysis and phenotypic and chemotaxonomic data, zrk23^T was considered to represent a novel species of the genus Sphingosinithalassobacter, for which the name Sphingosinithalassobacter tenebrarum sp. nov. is proposed. The type strain is zrk23^T (=KCTC 72896^T=MCCC 1K04416^T).