Amnimonas aquatica gen. nov., sp. nov., Isolated from a Freshwater River

A gram-stain-negative and strictly aerobic bacterium, designated strain HR-ET, was isolated from a water sample of the Han River in South Korea. Cells were catalase-negative and oxidase-positive motile rods with a flagellum. The strain grew at 10–37 °C and pH 7–8 and in the presence of 0–2% (w/v) NaCl. Ubiquinone-8 and summed features 3 (comprising C16:1ω7c and/or C16:1ω6c) and 8 (comprising C18:1ω7c and/or C18:1ω6c), C16:0, iso-C10:0 and C12:0 3-OH were identified as the major respiratory quinone and fatty acids (>5%), respectively. The 16S rRNA gene sequence of strain HR-ET shared the highest similarities with Perlucidibaca piscinae IMCC 1704T (98.1%), Perlucidibaca aquatica BK296T (96.8%), Paraperlucidibaca baekdonensis RL-2T (95.8%) and Paraperlucidibaca wandonensis WT-RY4T (95.7%). However, strain HR-ET formed a phylogenetic lineage distinct from members of the family Moraxellaceae, and a taxonomic analysis by RDP Naïve Bayesian rRNA Classifier classified strain HR-ET as a new genus of the family Moraxellaceae. In addition, analyses based on rpoD, secA and gyrB gene sequences also showed that strain HR-ET formed a lineage distinct from those of the genera Perlucidibaca and Paraperlucidibaca. Average nucleotide identity and in silico DNA–DNA hybridization values between strain HR-ET and the type strains of P. piscinae and P. aquatica were very low with 80.1 and 23.6% and 75.7 and 21.2%, respectively. The DNA G+C content was 67.0 mol%. Based on the phenotypic, genotypic and chemotaxonomic analyses, strain HR-ET represents a novel genus of the family Moraxellaceae, for which the name Amnimonas aquatica gen. nov., sp. nov. is proposed. The type strain of the type species is HR-ET (=KACC 19408T=JCM 32266T).