Probiotic Features of Three Lactic Acid Bacteria Strains Isolated from Foods and Characterization of Their Bioactive Molecules

Abstract

New probiotic strains of lactic acid bacteria (LAB) are needed to meet the increasing consumer demand for probiotics. Hence, the aim of the present study was to investigate the probiotic properties of three LAB strains, namely Lactiplantibacillus plantarum 4F, Lactiplantibacillus plantarum 4JC, and Lacticaseibacillus paracasei 3MI3 using several in vitro probiotic tests. Results revealed that all strains showed high survival rate (≥60%) under extreme conditions of the gastrointestinal tract (lysozyme, pepsin, and bile). They were also able to auto-aggregate and co-aggregate with different pathogens. Moreover, all strains exhibited high antioxidant activity and antimicrobial ability against nine pathogens (Salmonella typhimurium, Listeria monocytogenes, Klebsiella pneumonia, Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, Penicilium brasilianum, Aspergillus niger, and Fusarium oxysporum). HPLC and GC-MS analysis revealed the involvement of various organic and fatty acids in the observed antibacterial and antifungal activities. Lactic acid was the main produced compound with a significant concentration of 17.11 g/L. The biosafety assessment indicated that these strains were susceptible to most tested antibiotics, with no hemolytic and DNase activities. These findings reveal that the three studied strains of lactic acid bacteria have the potential to serve as novel probiotics in the development of functional products that promote health benefits.