molecular identification of lactobacillus acidophilus strain abc240 isolated from traditional yogurt and assessing its stability and safety as well as antibacterial and antioxidant activities

Background and objectives: in recent years, research has focused on the isolation of new bacterial strains with diverse and beneficially biological activities. this study investigated stability (under various acid concentrations, various bile-salt concentrations, cholesterol absorption ability and surface hydrophobicity) and antagonistic, antioxidant and immune activities of lactobacillus acidophilus strain abc240 isolated from traditional yogurts.materials and methods: strain was identified using polymerase chain reaction technique. its viability was assessed under acidic conditions (ph values of 3, 4 and 5) and in presence of bile salts (concentrations of 0.3, 0.5 and 0.7%). additionally, antimicrobial activity was assessed through well diffusion and disc diffusion methods. antioxidant capacity was assessed using abts (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) and dpph (2,2-diphenyl-1-picrylhydrazyl) assays. this study analyzed the microbial cell surface hydrophobicity, cholesterol absorption ability and safety parameters, including antibiotic sensitivity, hemolytic activity, dnase activity and biogenic amine production.results: results demonstrated high stability of this strain against various concentrations of acid (ph values of 3, 4 and 5) and bile salts (0.3, 0.5 and 0.7%). ability of lactobacillus acidophilus strain abc240 to absorb cholesterol included 43.60% ±0.66 and its cell surface hydrophobicity was assessed at 50.49% ±0.63. the antimicrobial potential assessments revealed strong activity against several bacterial species. furthermore, antioxidant activities, assessed using dpph and abts methods, were detected as 44.69% ±0.89 and 49.80% ±0.79, respectively, indicating the bacterial high potential in inhibiting free radicals. antibiotic sensitivity assay showed a non-growth zone diameter ranging from 13.20 mm ±0.55 (vancomycin) to 24.50 mm ±0.66 (chloramphenicol). lactobacillus acidophilus strain abc240 showed no hemolytic or dnase activity and did not produce biogenic amines.conclusions: in conclusion, lactobacillus acidophilus strain abc240 can be introduced as a new probiotic strain with biological and functional characteristics appropriate for use in the food industry.