Phylogeny of spore-forming lactic acid bacteria based on 16S rRNA gene sequences

The phylogeny of spore-forming lactic acid bacteria was investigated on the basis of 16S rRNA gene sequences. Sixteen strains were separated into three lines of descent; one consisted of 14 strains assigned to Sporolactobacillus spp. and Bacillus spp., and the other two each consisted of "Sporolactobacillus dextrus" and Bacillus coagulans. Strains of all the first lineage but one composed a cluster of similarity values of 97.2% and higher, and were represented by the type strain of S. inulinus. The cluster was further separated into five subclusters, four catalase negative and one positive. The definition of the genus Sporolactobacillus should be amended to accommodate catalase positive strains. Spore-forming lactic acid bacteria originated at different phylogenetic positions, and would have evolved convergently in the area of Bacillus.