Isolation of Lactic Acid Bacteria from Local Yogurt Samples in Chaharmahal and Bakhtiari Province: The Assessment of Probiotic Characteristics

Background and Aim: The present study investigates the probiotic, antibacterial, technological, and safety properties of lactic acid bacteria (LAB) isolated from traditional yogurt in Chaharmahal and Bakhtiari, Iran. Materials and Methods: After serial dilution, culture was carried out in MRS culture media with 19 distinct rods bacteria. The gram-positive and catalase-negative LAB isolates were identified using Gram Staining, catalase, H2S, Indole, Motility and Oxidase biochemical assays, carbohydrate fermentation patterns, and 16S rDNA analysis. Then their probiotic potential (resistance to stomach acid and bile salt, hydrophobicity, auto-aggregation and co-aggregation, adherence capacity, and safety analysis) was evaluated. Results: It was found that LAB strains belonged to Seven species belonging to five genera, including L. plantarum, L. brevis, L. rhamnosus, L. paracasei, L. casei, L. fermentum, and L. jensenii. After three hours of incubation at pH 2, strains lost 3–6 log units with L. rhamnosus strain IDC-D21 and L. paracasei strain DBR-D20, showing the most resilience to low pH and simulated GIT juices. The L. rhamnosus strain IDC-D21 and L. plantarum strain LRO-7 strains had the highest and lowest hydrophobicity (34.8 and 25.6%), respectively. Besides, the L. rhamnosus strain IDC-D21 had the highest degree of auto-aggregation (17.29%), followed by the L. paracasei strain DBR-D20 (14.28%). Also, the L. rhamnosus strain IDC-D21 showed the highest co-aggregation degree (19.07%). Conclusion: According to the research findings, L. rhamnosus strain IDC-D21 is recommended for application as a coculture in the dairy industry. Indeed, it has the best probiotic and technical features.