Evaluation des propriétés technologiques de souches de lactobacillus pour starters laitiers

Abstract

A total of 46 strains related to the genus Lactobacillus sensu lato were isolated and characterized based on their morphological, physiological, and biochemical properties. The strains S3, S13, S17, and S27 were identified using the API 50 CHL system as Lactobacillus brevis, Lactobacillus curvatus, Lactobacillus plantarum, and Lactobacillus paracasei subsp. paracasei, respectively, revealing an interesting microbiological diversity within the studied samples. The evaluation of technological properties showed that the strains exhibited good tolerance to NaCl concentrations of 2% and 4%, as well as a predominant production of β-galactosidase. Strains S23, S2, S3, and S4 demonstrated significant proteolytic activity, while positive lipolytic activity was observed in approximately 55% of the tested strains. In contrast, no exopolysaccharide production was detected. The assessment of functional properties revealed variable resistance to acidic conditions (pH 2 and pH 3) and bile salts, with strains S31 and S34 showing the highest tolerance. Furthermore, the strains exhibited stronger antimicrobial activity against Staphylococcus aureus than against Escherichia coli, indicating their ability to inhibit certain undesirable microorganisms. These results highlight the microbiological richness of local raw milk and emphasize the potential interest of certain strains for applications in the dairy industry. However, further studies are needed to deepen the characterization of these isolates and confirm their potential for practical use.