Diversity and functional properties ofLactobacillus plantarum-group strains isolated from Italian cheese products

The aim of this study was to characterize dairy Lactobacillus plantarum-group strains on the basis of their phenotypic and genotypic profiles in order to increase the knowledge on the ecology and biodiversity within this wild Lactobacillus group. In addition, their in vitro potential probiotic properties were evaluated with a view to identifying potential interesting applications. Among the strains, both physiological and biochemical characteristics differed noticeably, indicating biodiverse phenotypic differences. Genotyping experiments using randomly amplified polymorphic DNA (RAPD)-PCR with primer M13 also showed a remarkable heterogeneity among the strains and allowed the strains to be grouped into the species L. plantarum and L. pentosus/L. paraplantarum. With regard to probiotic functional characteristics, the L. plantarum strains 31C and 143C and the L. plantarum strains 64FS and 61FS, isolated from Caciotta and Fiore Sardo cheeses, respectively, survived simulated gastrointestinal conditions and were considered to be acid and bile tolerant. The majority of the strains exhibited antagonistic activity towards Escherichia coli ATCC 43895 and L. sakei DSM 20017, but only one of these strains was found to produce a bacteriocin-like compound. The results of this study suggest the presence of both phenotypic and genotypic variation within the L. plantarum group isolated from the two different Italian cheeses. Further investigation and development as potential probiotic strains is required.