Photobacterium obscurum sp. nov., a marine bacterium isolated from the coast of Qingdao

A Gram-stain-negative, facultative anaerobic, rod-shaped strain, named SDRW27 T , was isolated from offshore seawater collected near Qingdao. Strain SDRW27 T was able to grow at 16–37 °C (optimum, 28 °C), pH 6.0–9.0 (optimum, pH 6.0) and in the presence of 1–7 % (w/v) NaCl (optimum, 3 %). Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SDRW27 T was most closely related to Photobacterium toruni H01100410B T (97.89 % sequence similarity), Photobacterium andalusiense H01100409B T (97.89 %) and Photobacterium leiognathi ATCC 25521 T (97.82 %). The predominant fatty acids were summed feature 3 (C 16 : 1 ω7 c and/or iso-C 15 : 0 2-OH), summed feature 8 (C 18 : 1 ω 7 c and/or C 18 : 1 ω 6 c ) and C 16 : 0 . The polar lipids of strain SDRW27 T comprised phosphatidylglycerol, phosphatidylinositol dimannoside, phosphatidylcholine, phosphatidylethanolamine and three unidentified lipids. The major respiratory quinone was ubiquinone-8. The G+C content was 47.71 mol%. The genome size was 5.84 Mbp, including 85 contigs with an N50 value of 223 542. The average nucleotide identity (ANI) values of SDRW27 T with its three most similar strains, P. toruni H01100410B T , P. andalusiense H01100409B T and P. leiognathi ATCC 25521 T , were 71.36, 71.58 and 72.23 %, respectively (all lower than the 95–96 % ANI threshold), and the DNA–DNA hybridization (DDH) values were 20.4, 20.8 and 20.4 % (all lower than the 70 % DDH threshold). The obtained results of polyphasic analysis demonstrate that strain SDRW27 T represents a novel species, for which the name Photobacterium obscurum sp. nov. is proposed. The type strain is SDRW27 T (=MCCC 1K06286 T =KCTC 82892 T ).