Evaluation of probiotic potential of β-galactosidase producing Lactobacillus rhamnosus and their charaterization

Lactose intolerance is defined as the inability to digest lactose due to insufficient activity of the β-galactosidase enzyme, which catalyzes the hydrolysis of lactose into glucose and galactose. This study evaluated the potential probiotic properties of isolated Lactobacillus rhamnosus S8, which exhibiting high β-galactosidase activity. The strain demonstrated higher survival rate under gastrointestinal stress, with 80% and 63% viability after 3 h in simulated gastric fluid and 8 h in intestinal fluid, respectively, while retaining 60.8% and 47.8% of its enzymatic activity. Lb. rhamnosus S8 showed higher resistant to low pH (93% survival at pH 3.0), bile salts (68% survival at 0.4%), Additionally, Lb. rhamnosus S8 exhibits high antioxidant activity (70.6%), strong self-aggregation ability (95%), resistance to lysozyme (90.2%), and non-hemolytic activity. Furthermore, the prebiotics fructooligosaccharide and galactooligosaccharide significantly enhance the growth of Lb. rhamnosus S8, serving as valuable carbon sources for this strain. Overall, our systematic analysis reveals that Lb. rhamnosus S8 holds great promise for practical application as probiotics, particularly as a starter in lactose-containing fermented foods.