Bacillus siralis sp nov., a novel species from silage with a higher order structural attribute in the 16S rRNA genes

A novel bacterial strain (171544(T)) was recently isolated from silage and was classified in the genus Bacillus by 16S rDNA sequence analysis. Additio nal silage samples have been investigated in the present study and four org anisms resembling strain 171544(T) were isolated. Phenotypic and genotypic characterization of these bacteria showed that they constitute a new specie s of the genus Bacillus. This taxon was positioned in the family Bacillacea e on the basis of evolutionary distance trees using 16S rDNA sequences. Bac illus circulans, Bacillus firmus and Bacillus benzoevorans were the most cl osely related species with 16S rDNA similarities of 97.2, 96.3 and 95.9 %, respectively. All five silage isolates shared a higher order structural fea ture in the 3' region of the 16S rRNA gene comprising an extension to helix 49 of 24 bp and highly similar random amplified polymorphic DNA patterns t hat distinguished them from the type strains of B. circulans and B. firmus. Moreover, they possessed a unique pattern of phenotypic features including subterminally or terminally located endospores which distinctly swelled th e sporangium. strictly aerobic metabolism but with the ability to utilize n itrate as a terminal electron acceptor under anaerobic conditions, and hydr olysis of casein but not starch. The name Bacillus siralis is therefore pro posed for this new taxon. The type strain of B. siralis is strain 171544(T) (= NCIMB 13601(T) = CIP 106295(T)).