Ribotyping and biotyping of Lactobacillus helveticus from the koumiss

The lactic acid bacteria are very important components involved in the milk products processing. Lactobacillus helveticus, a homofermentative thermophilic lactobacillus commonly occurring in cheeses, has been isolated as the prevailing species in natural koumiss in this work. The species identification of six studied L. helveticus strains was based on rep-PCR fingerprinting with (GTG)₅ primer. Biotyping (API 50CH kit, conventional tests) showed phenotypic heterogeneity among isolates and enabled the identification to the genus Lactobacillus only. Ribotyping with restriction enzyme EcoRI yielded a strain-specific restriction patterns and allowed good strain differentiation. Obtained ribotypes of the isolates originating from the koumiss gave unique band patterns with low similarity to the selected reference cultures of L. helveticus. Despite low number of strains analyzed, the ribotype data showed certain heterogeneity that seemed to be not only strain dependent, but also related to the source of isolates. We concluded that analyzed isolates from koumiss represent a new ecovar, L. helveticus ecovar Koumiss.