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 zrk23T, 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 zrk23T within the genus Sphingosinithalassobacter and showed the highest similarity to Sphingosinithalassobacter portus FM6T (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 C16 : 0, C14 : 0 2-OH and summed feature 8 (C18 : 1ω7c and/or C18 : 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 zrk23T and the most closely related available genome, of Sphingosinithalassobacter portus FM6T, was 82.21 %, indicating that zrk23T was clearly distinguished from S. portus. The analysis of genome sequence of zrk23T revealed that there were many genes associated with degradation of aromatic compounds existing in the genome of zrk23T. As a result of the combination of the results of phylogenetic analysis and phenotypic and chemotaxonomic data, zrk23T 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 zrk23T (=KCTC 72896T=MCCC 1K04416T).