Functional properties of Lactobacillus plantarum strains: A multivariate screening study

• 32 Lactobacillus plantarum strains were screened for probiotic properties in vitro.
• A semi-quantitative scale was used to calculate a “probiotic score”.
• Multidimensional scaling was used to represent the pattern of probiotic properties.
• Strains source correlated with the probiotic scores.

Thirty-two Lactobacillus plantarum strains isolated from different sources were genetically characterized at subspecies level with recA gene based multiplex PCR and pulsed-field electrophoresis.All the strains were tested in vitro for functional properties (ability to form biofilms, agglutination of yeast cells, bile salt hydrolase activity, β-galactosidase activity, surface hydrophobicity, resistance to lysozyme, gastric juice and bile salts), for antimicrobial activity and for antibiotic resistance. The presence of bsh and msa genes and of the pln bacteriocin loci were also evaluated.Hierarchical cluster analysis was used to identify eight different plantaritypes sharing similar patterns of pln loci. A global functional score was calculated by transforming values for continuous in vitro functional properties in an ordinal scale by cluster analysis, while a nominal scale was used for the other properties. Multidimensional scaling was used to evaluate the similarity in functional properties among the isolates and to evaluate the relationships between source of isolation and functional properties.Nine strains showed the best in vitro functional potential and a significant relationship was found between source of isolation and functional score.This study confirmed a high heterogeneity in functional properties among L. plantarum strains and provides insight for optimal screening strategies.