Polaribacter uvawellassae sp. nov., a Member of the Family Flavobacteriaceae Isolated from Mud Crab (Scylla serrata).

A Gram-stain-negative, strictly aerobic, rod-shaped, and no flagella, designated SLMDC-22, was isolated from the intestine of a mud crab (Scylla serrata). The molecular phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SLMDC-22 belonged to the genus Polaribacter and exhibited 96.9% similarity to P. huanghezhanensis, 96.5% to P. pacificus, 95.8% to P. lacunae, and 94.1% to P. marinivivus. The G + C content of the DNA of strain SLMDC-22 was 30.3%. Growth occurred at 4-34 °C (optimum, 23 °C), at pH 5-9 (optimum, pH 7.0), and with 0.5-2.0% (w/v) NaCl (optimum, 2%). The major fatty acid was iso-C. Major polar lipids include phospholipid, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, amino lipid, glycolipid, amino phospholipid, and an unknown polar lipid. The major respiratory quinone is MK-6. Based on whole-genome analysis, the orthologous average nucleotide identity (ANI) with the two closest relatives, Polaribacter huanghezhanensis and Polaribacter pacificus, were 87.3% and 75.7%, respectively. Furthermore, the digital DNA-DNA hybridization (dDDH) values against Polaribacter huanghezhanensis and Polaribacter pacificus were 75.8% and 19.6%, respectively. Notably, 25 genes of SLMDC-22 were associated with nitrogen metabolism, including denitrification, nitrate ammonification, ammonium assimilation, and nitrosative stress. The phenotypic, genotypic, phylogenetic, and chemotaxonomic data revealed that strain SLMDC-22 represents a novel species of the genus Polaribacter, for which the name Polaribacter uvawellassae sp. nov. is proposed. The type strain is SLMDC-22 (= KCTC 102289 = MCCC 1K09222).