Flavonifractor porci sp. nov. and Flintibacter porci sp. nov., two novel butyrate-producing bacteria of the family Oscillospiraceae.

Two Gram-stain-negative, strictly anaerobic, non-motile, non--spore-forming and rod-shaped bacterial strains, namely, P01024(T) and P01025(T), were isolated from piglet manure. The strains P01024(T) and P01025(T) fermented glucose to acetate and butyrate. The major cellular fatty acids (>10.0%) of strain P01024(T) were C(14 : 0), C(16 : 0) and summed feature 9 (iso-C(17:1) ω9c and/or 10-Methyl-C(16:0)) and of strain P01025(T) were C(14 : 0), C(16 : 0) and summed feature 3 (C(16 : 1)  ω6c and/or C(16 : 1)  ω7c). Analysis of 16S rRNA gene sequences indicated that strains P01024(T) and P01025(T) belonged to the family Oscillospiraceae. The strain P01024(T) showed high identities of 16S rRNA genes to type species Flavonifractor plautii ATCC 29863(T) (96.64%). The highest percentages of conserved protein (POCP) value between strain P01024(T) and Flavonifractor plautii ATCC 29863(T) was 59.84%. The average nt identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain P01024(T) and Flavonifractor plautii ATCC 29863(T) were 79.51% and 23.80%, respectively, supporting that strain P01024(T) represented a novel species of the genus Flavonifractor. Strain P01025(T) showed high identities of 16S rRNA genes to the type species Flintibacter butyricus BLS21(T) (95.87%). The highest POCP and AAI (average aa identity) values of strains P01025(T) to Flintibacter hominis New-19(T) were 53.02% and 73.11%, respectively. The ANI and dDDH values between strains P01025(T) and Flintibacter hominis New-19(T) were 75.44% and 23.40%, respectively, supporting that strain P01025(T) represented a novel species in the genus Flintibacter. The calculated G+C molar contents for strains P01024(T) and P01025(T) were 58.43 and 56.44 mol%, respectively. Together with phenotypic features, we concluded that strains P01024(T) and P01025(T) represented novel species in the genera Flavonifractor and Flintibacter of the family Oscillospiraceae, respectively, for which the names Flavonifractor porci sp. nov. (type strain P01024(T)=CGMCC 1.18055(T)=KCTC 25793(T)) and Flintibacter porci sp. nov. (type strain P01025(T)=CGMCC 1.18060(T)=KCTC 25794(T)) are proposed.