Ribotyping of Lactobacillus helveticus from the Koumiss
| Authors | |
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| Year of publication | 2005 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | The lactic acid bacteria (LAB) are very important components of the formation of milk products. Lactobacillus helveticus, a homofermentative thermophilic LAB largely presented in cheeses, has been found to be the prevalent species in natural koumiss. A collection of six L. helveticus strains supplemented with reference cultures was studied for its phenotypic characters, as well as for genotyping. Biotyping (API 50CH kit, tube tests) confirmed that isolates belong to the genus Lactobacillus, but it was not suitable for identification to the species level. A phenotypic heterogeneity among L. helveticus isolates was observed, mainly in acid formation from sugars. Ribotyping (EcoRI, DNA probe complementary to 16S and 23S rRNA) yielded a variety of restriction patterns and allowed good strain differentiation. Obtained ribotypes of analyzed isolates gave unique band patterns with no relationship to the selected reference cultures. Despite the low number of strains analyzed, the ribotype data of isolates and reference cultures showed an interesting strain heterogeneity, that seemed not only strain dependent, but also related to the source of isolates. Ribotyping is considered a powerful discriminatory tool for diversity study among strains belonging to the same species. We concluded that analysed isolates from koumiss represent a new L. helveticus ecovar. |
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