Caractérisation in vitro du potentiel probiotique de souches de bactéries lactiques isolées de produits laitiers traditionnels

Abstract

This study focuses on the isolation, characterization, and evaluation of the technological, functional, and probiotic properties of lactic acid bacteria (LAB) isolated from traditional Algerian fermented products. A total of 46 isolates were obtained from eight types of products collected in five regions (Aïn Témouchent, Chlef, Biskra, Oran, and Touggourt). Morphological, biochemical, and physiological characterization confirmed their belonging to the LAB group. API gallery identification revealed several species, including Lacticaseibacillus rhamnosus (LA2), Lactiplantibacillus plantarum (LB4), Levilactobacillu brevis (VC2), Lactococcus lactis subsp. cremoris (FA3), Leuconostoc spp. (FA6 and LCT1), and Enterococcus faecium (LC8), reflecting the microbiological diversity of traditional Algerian fermentations. Evaluation of technological properties revealed variable proteolytic and acidifying activity across strains, a complete absence of lipolytic activity, and heterogeneous exopolysaccharide and biofilm production. Antioxidant activity, measured by the DPPH assay, showed high inhibition rates for strains FO1 (93.5%), LB6 (93.4%), and FA1 (89.4%). In vitro evaluation of probiotic properties demonstrated variable resistance to gastric acidity (pH 2 and pH 3), digestive enzymes (pepsin and trypsin), and bile salts (Oxgall 0.1%, 0.3%, and 0.5%). Strains LB6, LC3, LA1, and FO1 distinguished themselves through overall performance, confirming their probiotic potential. These results highlight the microbiological richness of traditional Algerian fermented products and open perspectives for the development of locally sourced probiotics.