Acidaminococcus nyctereutis sp. nov., a bacterium isolated from the gut of a raccoon dog (Nyctereutes procyonoides)

A strictly anaerobic bacterial strain, designated LBK-2^T, was isolated from the intestinal tract of a raccoon dog. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain LBK-2^T shared the highest similarity (99.3 -95.0 %) with type strains in the genus <i>Acidaminococcus</i>. The cells were coccoid, Gram-negative, non-motile and non-haemolytic. They tested negative for oxidase and catalase but positive for alkaline phosphatase. Growth occurred at 20-50℃ (optimum: 37 ℃), pH 3.5-8.0 (optimum: pH 7.0) and 0-2 % NaCl. Major fatty acids include C_{16 : 1} <i> </i>ω<i>9c</i>, C_{18 : 1} <i> </i>ω<i>9c</i>, C_{12 : 0} and C_{12 : 0} aldehyde. The average nucleotide identity and digital DNA-DNA hybridization values between LBK-2^T and type strains of other <i>Acidaminococcus</i> species ranged from 64.83 to 88.25 % and 18.0 to 64.6 %, respectively, both below the species delineation thresholds. The genomic DNA G+C content was 53.6 %. Based on polyphasic taxonomic evidence, strain LBK-2^T (=CGMCC 1.18153^T=KCTC 25959^T) represents a novel species within the genus <i>Acidaminococcus</i>, for which the name <i>Acidaminococcus nyctereutis</i> sp. nov. is proposed.