Postbiotic cell free supernatant from Lactobacillus strain: Isolation, characterization, In vitro assessment of antimicrobial and cytotoxic potentials using Vero cell line

This study investigates the isolation, identification, and characterization of a Lactobacillus paracasei strain derived from homemade yogurt, emphasizing its potential as a source of bioactive postbiotics. Using morphological and biochemical methods, including MALDI-TOF MS, the strain was reliably identified at the genus and species levels. The probiotic nature of the isolate was confirmed through culture and microscopic analysis. The research further explored the production of postbiotic cell-free supernatants from the isolated strain, assessing their antimicrobial and cytotoxic activities. The postbiotics demonstrated significant inhibitory effects against pathogenic bacteria such as Escherichia coli, Salmonella enterica, Streptococcus bovis, and Enterococcus faecalis, often exhibiting antimicrobial efficacy comparable or superior to standard antibiotics. The safety profile was affirmed by cytotoxicity assays on Vero cell lines, underscoring their low toxicity and potential for safe therapeutic application. The findings support the notion that postbiotics hold promising prospects as natural antimicrobial agents, especially in light of rising antibiotic resistance. Their stability and ease of handling offer advantages over live probiotics. The study emphasizes the importance of further clinical investigations and mechanistic studies to optimize the application of postbiotics in medical and food industry contexts, promoting safer and more effective health interventions.