E merging probiotics, parabiotics and postbiotics derived from lactic acid bacteria based on their resilience on stressful conditions and ability to form biofilm

Abstract

This study examinates certain probiotic properties and two biologicals activities of two bacterial strains, Streptococcus thermophilus isolated from natural yogurt, and Lactobacillus plantarum 299v a commercially available strain. The results indicate that the two LAB strains have demonstrated considerable probiotic potential. They exhibited high temperature resistance and strong survivability under stimulated gastrointestinal conditions, tolerating low pH levels of 2 and 3 for 3h. They also showed good tolerance to bile salts at different concentrations (0,05%,0,1% and 0,2%), Regarding the antibiotic resistance, S. thermophilus and L. plantarum 299v were resistant to 4 antibiotics tested and considerable antibacterial activity of S. thermophilus against S. aureus ATCC6528. The strains displayed also favorable adhesive properties, including high auto-aggregation ability (62,30% for S. thermophilus, 61,36% for L. plantarum 299v), and high degree of co-aggregation (61,66%). as regards biological activities, the results also showed that the live and killed bacteria and their postbiotic derivatives have demonstrated a good iron and cholesterol reduction. This research may represent a first step in assessing the probiotic potential of the bacterial strains tested. With further supporting tests, these strains may prove to be a promising approach to managing oxidative stress indicators and cholesterol levels