Pararoseburia lenta gen. nov., sp. nov. isolated from human faeces

Y A strictly anaerobic, motile bacterium, designated as strain NSJ-9(T), was isolated from human faeces. Cells were Gram-negative, non-spore-forming, non-pigmented, and spiral-shaped or slightly curved rods with flagella. Optimal growth in M2GSC medium was observed at 37 degrees C (growth range 30-45 degrees C) and pH 6.5-7.0 (growth range 6.5-7.5) under anaerobic conditions. Phylogenetic analysis of the 16S rRNA gene revealed that strain NSJ-9(T) formed a distinct phylogenetic lineage that reflects a new genus in the family Lachnospiraceae, with high levels of similarity to Roseburia hominis A2-183(T) (95.2%), Roseburia cecicola ATCC 33874(T) (95.2%), Pseudobutyrivibrio ruminis DSM 9787(T) (95.2%), Pseudobutyrivibrio xylanivorans MZ 5(T) (94.8%) and Roseburia faecis M72/1(T) (94.4%). Genomic similarity (average nucleotide identity and digital DNA-DNA hybridization) values between strain NSJ-9(T) and its phylogenetic neighbours were below 71 and 31%, respectively, indicating that strain NSJ-9(T) represented a novel species. The average amino acid identity and the percentage of conserved proteins between strain NSJ-9(T) and other related members of the family Lachnospiraceae were below 63 and 50%, respectively, supporting that strain NSJ-9(T) was a member of a new genus. The predominant cellular fatty acids of strain NSJ-9(T) were C-16:0 and C-17:0 2-OH, and major polar lipids were glycolipids. The end products of glucose fermentation were acetate, propionate, iso-butyrate, butyrate and valerate. Phylogenetic and phylogenomic lineage, pairwise determined genome identity analysis suggested that strain NSJ-9(T) represents a novel genus in the family Lachnospiraceae. The genome size of strain NSJ-9(T) is 2.56 Mbp with 44.9 mol% G+C content. Collectively, the genotypic and phenotypic differences between phylogenetic relatives suggested strain NSJ-9(T) represented a novel species of a new genus, for which the name Pararoseburia lenta gen. nov., sp. nov. is proposed. The type strain of Pararoseburia lenta is NSJ-9(T) (=CGMCC 1.32469(T)=KCTC 15957(T)).