Molecular diversity among natural populations of Lactobacillus paracasei and Lactobacillus plantarum/paraplantarum strains isolated from autochthonous dairy products

Abstract

The diversity of 87 Lactobacillus paracasei and Lactobacillus plantarum/paraplantarum strains, previously identified from different autochthonous dairy products, was investigated by phenotypic and genotypic approaches. The increased resolution obtained using phenotypic and genotypic characterization allowed the level of strain heterogeneity detection to be widened. Phenotypic diversity was evaluated by studying biochemical characteristics of technological interest, including antimicrobial and proteinase activities, resistance to nisin, aggregation ability, production of exopolysaccharides, acetoin and diacetyl, citrate utilization, and antibiotic susceptibility. Genotypic diversity was generally evaluated by PCR amplification of repetitive bacterial DNA element fingerprinting using the (GTG) 5 primer [(GTG) 5 -PCR]. Moreover, in cases where strains were not discriminated by (GTG) 5 -PCR combined with phenotypic analysis, pulsedfield gel electrophoresis (PFGE) analysis was performed.The results indicate that L. plantarum/paraplantarum and L. paracasei natural isolates from artisanal dairy products are a gold mine in terms of diversity of strains and could be potentially interesting to dairy companies for the formulation of functional starter cultures in the production of innovative foods.

New Insight into Biofilm Formation Ability, the Presence of Virulence Genes and Probiotic Potential of Enterococcus sp. Dairy Isolates

“…Phylogenetic analysis of 16S rDNA sequences separated selected enterococci isolates into two distinct phylogenetic groups A and B generally following the geographic distribution of the isolates (Figure 3 ). The broad strain diversity correlated with the diverse origin of the isolates probably due to different environmental pressures, similarly to other LAB strains (Giraffa, 2003 ; Golic et al, 2012 ). In addition, the strains were clustered based on phenotypic traits using Jaccard dissimilarity measure resulting in seven distinct groups I-VII (Figure 3 ), comprising the isolates resistant to gentamicin (I), able to form biofilm and resistant to ciprofloxacin (II), the isolates with virulence genes (III, IV, and V), and the isolates with gelatinase (VI) and hemolytic (VII) activity, respectively.…”

Evaluation of probiotic potential of yeasts isolated from traditional cheeses manufactured in Serbia and Croatia

“…The Western Balkan Countries (WBC) harbour a variety of traditional fermented foods produced by spontaneous or controlled fermentation from cow’s, ewe’s and goat’s milk. These products feature a rich diversity of lactic acid bacteria (LAB) as part of their natural microflora, with relevant genetic, metabolic and technological features, making these bacteria potential candidates as probiotic microorganisms [ 1 - 6 ]. However, the diversity and probiotic potential of yeasts in WBC artisanal dairy products is still insufficiently explored.…”