Probiotic Properties and Physicochemical Potential of Lactic Acid Bacteria Isolated from Moroccan Table Olives

Background: Lactic Acid Bacteria are a group of Gram-positive bacteria which are widely used in the food industry as organic ferments called starter cultures. In this study, Enterococcus faecium, Leuconostoc mesenteroides, Lactococcus lactis, Weissella paramesenteroides, and Lactiplantibacillus plantarum isolated from Moroccan table olives were tested for their acquisition of probiotic and technological properties. Methods: The 5 strains were previously isolated from table olives in 2017. Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometer (MALDI-TOF MS) and intergenic space sequencing were used for molecular identification. Following that, probiotic and physicochemical properties were evaluated, including growth at different pH levels (2, 3, and 10), temperatures (7, 45, and 50 °C), and sodium chloride (NaCl) concentrations (6.5 and 18% m/v). Antibacterial activity was tested out against Gram-positive and Gram-negatives bacteria. Results: The 5 strains (E. faecium 168, L. lactis 9, L. plantarum 11, L. mesenteroides 62, and W. paramesenteroides 36) showed an ability to grow at low temperatures (7 °C). L. lactis 9 and L. plantarum 11 showed higher acid (pH 2) and salt (18% NaCl) tolerances. In addition, L. lactis 9 and L. plantarum 11 exhibited the highest level of free radical scavenging activity after 48 h of incubation, respectively). L. plantarum 11 and E. faecium 168 showed the highest antibacterial capacity. However, E. faecium 168 and W. paramesenteroides 36 demonstrated better and more rapid acid production capabilities. Conclusion: L. plantarum 11, E. faecium 168, and W. paramesenteroides 36 were considered the best candidates as probiotic cultures for further in vivo studies and functional food product development.