| Abstract |
A Gram-negative aerobic bacterium, designated RR4-38T,
was isolated from a biofilter in a seawater recirculating aquaculture
system (RAS) in Busan, South Korea. The bacteria
were irregular, short, rod-shaped, non-motile, oxidase-positive,
and catalase-negative. Growth of the strain RR4-38T
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 RR4-38T 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
RR4-38T and the two closest strains, Ulvibacter antarcticus
DSM 23424T and Aureitalea marina S1-66T, 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-
C15:0 (26.5%), iso-C17:0 3-OH (16.4%), iso-C15:1 G (15%), and
iso-C16:0 3-OH (9.6%). The major cellular polar lipids were
diphosphatidylglycerol, phosphatidylethanolamine, unidentified
aminolipids, and glycolipids. Based on phenotypic, chemotaxonomic,
and phylogenetic features, strain RR4-38T 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 RR4-38T (= KCTC 52651T
= DSM 108068T). |
