Fluviispira sanaruensis sp., nov., Isolated from a Brackish Lake in Hamamatsu, Japan

Strain RF1110005T, which was isolated from brackish lake water sampled at Lake Sanaru in Japan as a “filterable” bacterial strain, was characterized as a novel species in the genus Fluviispira, family Silvanigrellaceae, order Silvanigrellales, the class Oligoflexia and the phylum Bdellovibrionota. Cells of RF1110005T were aerobic, Gram stain negative, and show a pleomorphic morphology of spiral, filamentous and rod shapes. Catalase reaction was positive. Strain RF1110005T grew optimally at 30 °C, pH 7.0–8.0 and 0.5% NaCl (w/v). The major polar lipids in RF1110005T were phosphatidylethanolamine and phosphatidylglycerol. The predominant cellular fatty acids were iso-C15:0 and anteiso-C15:0. Phylogenetic analysis based on 16S rRNA gene sequences and concatenates of core gene sequence showed that the nearest neighbor of strain RF1110005T was Fluviispira multicolorata strain 33A1-SZDPT with 98.4% 16S rRNA gene sequence similarity. The genome size of strain RF1110005T was 3.5 Mbp with two plasmids (80 kb and 69 kb), and the G + C content was 33.7 mol%. Comparisons with genome-wide analyses and chemotaxonomic characters clearly showed that strain RF1110005T differed from F. multicolorata. Therefore, a novel species in Fluviispira sanaruensis, sp. nov., is proposed for strain RF1110005T (= JCM 31447 T = LMG 30360 T).