Summary auto-generated
Researchers describe Bacillus ruris, a novel bacterial species isolated from raw milk and feed concentrate on dairy farms. Four strains were identified through polyphasic taxonomic analysis, including molecular, biochemical, and morphological characterization. The isolates were heat-treated at 100°C for 30 minutes to select for highly heat-resistant spores. B. ruris is a motile, Gram-positive, rod-shaped bacterium that forms ellipsoidal endospores within swollen sporangia. Phylogenetic analysis using 16S rRNA gene sequences showed 98.3% similarity to the closest known relative, Bacillus galactosidilyticus, but DNA-DNA hybridization revealed only 32.5% relatedness, confirming this as a distinct species. The bacteria differ from B. galactosidilyticus in morphology, acid production patterns across various substrates, and fatty acid composition. B. ruris is facultatively anaerobic, catalase-positive, and grows at 30-40°C and pH 6-11. The type strain LMG 22866T has a DNA G+C content of 39.2 mol%. These findings establish B. ruris as a new species within the genus Bacillus relevant to dairy farm microbiology.
Key findings
- Four novel Bacillus isolates from dairy farms constitute a new species, Bacillus ruris, distinguished by ellipsoidal spores in swollen sporangia and unique biochemical profiles
- 16S rRNA sequencing showed 98.3% similarity to B. galactosidilyticus, but DNA-DNA relatedness was only 32.5%, confirming species-level distinction
- B. ruris produces acid from a wide range of substrates after 48 hours and differs from related species in fatty acid composition, particularly in C15:0, anteiso-C15:0, and C16:0 content
- The type strain LMG 22866T is facultatively anaerobic, catalase-positive, with a DNA G+C content of 39.2 mol%, and grows at temperatures between 30-40°C
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
Four novel ellipsoidal spore-forming Bacillus isolates with swollen sporangia, isolated from raw milk and feed concentrate, showed a high level of similarity in SDS-PAGE, fatty acid methyl esters and routine phenotypic tests. However, 16S rRNA gene sequence comparisons showed that this taxon was different from other related Bacillus species, and only a low level of DNA relatedness was found with the closest phylogenetic and phenotypic relative, Bacillus galactosidilyticus. This taxon could be differentiated from B. galactosidilyticus on the basis of morphological differences, stronger acid reactions with a wide range of substrates after 48 h incubation, and qualitative and quantitative differences in fatty acid content. On the basis of these data, a novel species, Bacillus ruris sp. nov., is proposed, with LMG 22866T (=DSM 17057T) as the type strain.