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

A gram-stain-negative and strictly aerobic bacterium, designated strain HR-E^T, 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 C_16:1ω7c and/or C_16:1ω6c) and 8 (comprising C_18:1ω7c and/or C_18:1ω6c), C_16:0, iso-C_10:0 and C_12:0 3-OH were identified as the major respiratory quinone and fatty acids (>5%), respectively. The 16S rRNA gene sequence of strain HR-E^T shared the highest similarities with Perlucidibaca piscinae IMCC 1704^T (98.1%), Perlucidibaca aquatica BK296^T (96.8%), Paraperlucidibaca baekdonensis RL-2^T (95.8%) and Paraperlucidibaca wandonensis WT-RY4^T (95.7%). However, strain HR-E^T formed a phylogenetic lineage distinct from members of the family Moraxellaceae, and a taxonomic analysis by RDP Naïve Bayesian rRNA Classifier classified strain HR-E^T as a new genus of the family Moraxellaceae. In addition, analyses based on rpoD, secA and gyrB gene sequences also showed that strain HR-E^T 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-E^T 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-E^T 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-E^T (=KACC 19408^T=JCM 32266^T).