Pikeienuella piscinae gen. nov., sp. nov., a novel genus in the family Rhodobacteraceae.

A novel bacterium, designated strain RR4-56, was isolated from a biofilter of a seawater recirculating aquaculture system. The 16S rRNA gene sequence analysis showed that the isolate was closely related to Halovulum dunhuangense YYQ-30 (92.6%), Albimonas donghaensis DS2 (91.3%), Pontivivens insulae GYSW-23 (91.3%), and Monaibacterium marinum C7 (90.9%), belonging to the family Rhodobacteraceae. The strain was aerobic, Gram-negative, rod-shaped, oxidase-positive, and catalase-negative. Its optimum temperature, pH, and salinity for growth were 25-30°C, pH 8.5, and 2-3% NaCl (w/v), respectively. Its growth occurred at 15-35°C, pH 5.0-9.5, and 0-7% NaCl (w/v). It contained ubiquinone-10 (Q-10), a respiratory quinone, and the major cellular fatty acids were 11-methyl C ω7c (31.9%), C ω6c (30.4%), and C cyclo ω8c (16.1%). The polar lipids present in the strain were phosphatidylglycerol, an unidentified phospholipid, and an unidentified aminolipid. The strain had one 4,373,045 bp circular chromosome with G + C contents of 65.9 mol% including 4,169 genes, 4,118 coding sequences (CDSs), 3 rRNAs, and 45 tRNAs. Genome annotation predicted some gene clusters related to the degradation of several types of organic matter such as protocatechuate, catechol, and phthalate. Based on the polyphasic characteristics, RR4-56 represents a novel genus and species in the family Rhodobacteraceae, for which the name Pikeienuella piscinae gen. nov., sp. nov. was proposed. The type strain is RR4-56 (= KCTC 52648 = DSM 107918).