Pukyongia salina gen. nov., sp. nov., a novel genus in the family Flavobacteriaceae

A Gram-negative aerobic bacterium, designated RR4-38 T , was isolated from a biofilter in a seawater recirculating aqua-culture system (RAS) in Busan, South Korea. The bacteria were irregular, short, rod-shaped, non-motile, oxidase-positive, and catalase-negative. Growth of the strain RR4-38 T was observed at 15–35·C (optimum, 25–30·C), pH 5.5–9.5 (optimum, pH 8.0), and in the presence of 0–5% (w/v) NaCl (optimum, 3%). Phylogenetic analysis based on the 16S rRNA gene sequences showed that the strain RR4-38 T formed a distinct lineage with close genera Ulvibacter (≤ 95.01% 16S rRNA gene sequence similarity), Aureitalea (94.74%), Aureisphaera (≤ 93.27%), and Jejudonia (93.07%) that all belong to the family Flavobacteriaceae. Whole-genome sequence comparison revealed that the ANI (average nucleotide identity) and digital DDH (DNA-DNA hybridization) values between strain RR4-38 T and the two closest strains, Ulvibacter antarcticus DSM 23424 T and Aureitalea marina S1-66 T , were 68.96–69.88% and 17.4–19%, respectively. The genome analysis revealed that the strain might be involved in biodegradation of organic debris produced by farmed fish in aquaculture systems. The predominant respiratory quinone was menaquinone MK-6 and the major cellular fatty acids were iso-C 15:0 (26.5%), iso-C 17:0 3-OH (16.4%), iso-C 15:1 G (15%), and iso-C 16:0 3-OH (9.6%). The major cellular polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, unidentified aminolipids, and glycolipids. Based on phenotypic, chemotaxonomic, and phylogenetic features, strain RR4-38 t represents a novel genus and species in the family Flavobacteriaceae , for which the name Pukyongia salina gen. nov., sp. nov. is proposed. The type strain is RR4-38 T (= KCTC 52651 T = DSM 108068 T ).