A Comparative Study of Probiotic Potential of Two Lactic Acid Bacteria Isolates Obtained From Cereal-Based Products

Subject. Over the past few decades, interest in probiotics and functional foods has significantly increased across many countries worldwide, accompanied by growing attention to healthy lifestyles. This trend indicates a need for new probiotic strains, especially those derived from underexplored plant sources, as they may prove to be ideal candidates for use in non-dairy functional products. Purpose. To assess and compare the probiotic potential of two lactic acid bacteria isolates obtained from barley and oat processing products. Methods. The purity of the cultures was determined using standard microbiological techniques. Species identification of the isolates was performed based on a combination of morphological, physiological-biochemical, and cultural characteristics. Stress tolerance was assessed by evaluating the survival of the studied microorganisms after exposure to artificial saliva (0.5 h), physiological saline with pH 2.5 (1 h), and a mixture of bile and artificial duodenal juice (2 h). Antibiotic susceptibility was determined using the disk diffusion method. Results. It was established that the isolate obtained from the barley-based product belongs to the species Lacticaseibacillus casei, while the one from the oat-based product belongs to the species Companilactobacillus nantensis. Their survival rates under simulated conditions of saliva, stomach, and small intestine was 97.12 ± 1.81%, 96.73 ± 0.35%, and 85.46 ± 2.45% for L. casei, and 98.30 ± 0.42%, 97.91 ± 1.39%, and 84.14 ± 1.58% for C. nantensis, respectively – all of which are considered high. Both cultures were sensitive to a range of antibiotics but resistant to kanamycin and streptomycin, indicating the need for further genetic investigation. Scope of results. The findings indicate a high probiotic potential of lactic acid bacteria isolated from lesser-studied plant sources – specifically, barley and oat processing products – and suggest the possibility of further research and application of L. casei and C. nantensis isolates in the food or medical industries.