Lactobacillus paracasei subsp paracasei heterogeneity:: The diversity among strains isolated from traditional Greek cheeses

Twenty-seven strains isolated from traditional Greek cheeses and phenotypically identified as L. paracasei sub-sp. paracasei were studied for their diversity in genetic and some biotechnological characteristics. Strain identification was confirmed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of whole-cell proteins, except for one strain. Six SDS-PAGE clusters were distinguished at a similarity level of 68%. RAPD-PCR was also used for typing of the strains and this confirmed the re-sults of SDS-PAGE, concerning the identity of the strains. According to their genetic relatedness, three distinct clusters of L. paracasei subsp. paracasei strains with an internal correlation coefficient (r) ranging from 55.4 to 62.6% were formed. The strains differed in both the number and molecular weights of plasmids harboured. Biotypes were found which differed in terms of acidifying, caseinolytic and aminopeptidase activities.