Oscillibacter ruminantium sp. nov., isolated from the rumen of Korean native cattle

Abstract

A strictly anaerobic, Gram-negative, non-spore-forming bacterium, designated GH1T, was isolated from the rumen of Korean native cattle (HanWoo). Cells were straight to slightly curved rods (2.0-4.5 mm long) and were motile by peritrichous flagella. The isolate grew at 30-45 °C (optimum 40 °C), at pH 5.5-6.5 (optimum pH 6.0) and with up to 3.5% (w/v) NaCl. Strain GH1T produced acid from D-glucose, D-ribose and D-xylose, with butyric acid being the major end product. The genomic DNA G+C content was 54.6 mol%. Based on comparative 16S rRNA gene sequence analysis, strain GH1T was most closely related to Oscillibacter valericigenes Sjm18-20T (97.3% 16S rRNA gene sequence similarity). DNA-DNA hybridization between strain GH1T and O. valericigenes DSM 18026T showed 24% reassociation. The major fatty acids were iso-C13: 0 (13.0 %), iso-C15: 0 (17.6 %), anteiso-C15: 0 (8.4 %) and C14: 0 (4.1 %), and the cellular fatty acid methyl esters as dimethylacetals (DMAs) were C16: 0 DMA (17.8 %), iso-C15: 0 DMA (15.2 %) and C14: 0 DMA (4.52 %). The cell-wall peptidoglycan of strain GH1T contained mesodiaminopimelic acid and the major cell-wall sugar was galactose. Based on 16S rRNA gene sequence similarity, phylogenetic analysis, DNA G+C content, DNA-DNA relatedness and distinct phenotypic characteristics, strain GH1T is classified in the genus Oscillibacter as a member of a novel species, for which the name Oscillibacter ruminantium sp. nov. is proposed. The type strain is GH1T (=KCTC 15176T=NBRC 108824T=JCM 18333T).