Abstract

Dichotomous keys based on morphological, cultural and biochemical tests have long been used to identify Bacillus species. The analysis of 16S rDNA is suggested to be used for identification that is more exact. The present study was carried out to compare a conventional phenotypic method with the analysis of the 16S rRNA andgyrB gene for better identification, to determine their phylogenetic relationships and to contribute to selecting starter cultures for Mbuja production. Twenty-six (26) Bacillusstrains isolated from 12 samples of Mbuja formerly identified by phenotyping as representatives of eight species (licheniformis, polymyxa, laterosporus, cereus,circulans, subtilis, pumilus and brevis) were studied. Results of genotypic analyses were not concurrent with previous phenotypic identification. Bacillus from different species were able to cluster together to form phylogenetic groups. An insight of these groups revealed important genetic diversity between strains from the same species.Bacillus subtilis and close relatives were the most abundant and presented appreciable biochemical traits. This group could therefore be considered for starter selection.

Key words: Mbuja, Bacillus sp., phenotyping, genotyping, starter.