Novel isolates of lactobacilli from fermented Portuguese olive as potential probiotics

- Wild lactobacilli in Portuguese fermented olives were screened for probiotic potential.
- Probiotic strains were able to breakdown oleuropein and peptides.
- Probiotic strains were able to withstand simulated gastrointestinal conditions.
- Probiotic strains exhibited antimicrobial features against food-borne pathogens.
- Probiotic strains exhibited distinct sensitiveness against antibiotics.

The purpose of this work was to screen for and characterize the potential probiotic features of strains of lactic acid bacteria isolated from Galega cultivar fermented olives, to eventually develop an improved probiotic food from plant origin. From 156 isolated strains, 10 were acid - and bile salt tolerant, and exhibited survival rates up to 48%, following simulated digestion. All strains exhibited auto- (4-12%) and co-aggregation features (≥30%), as well as hydrophobicity (5-20%) and exopolysaccharide-producing abilities, while no strain possessed haemolytic capacity or ability to hydrolyse mucin. Antibiotic resistance, oleuropein degradation, proteolytic activity and antimicrobial activity were strain-dependent features. Overall, 10 strains - belonging to Lactobacillus plantarum and Lactobacillus paraplantarum, appear to possess a probiotic value.