Characterization and Functional Properties of Lactobacilli Isolated from Kefir Grains

As a natural, symbiotic consortium of bacteria and yeasts, kefir grains provide a unique source of new probiotic microorganisms. In this work, three new isolates of lactobacilli, Lactobacillus helveticus and two strains of Lacticaseibacillus paracasei , were isolated from kefir grains originating from the North Caucasus region of Russia, and they were identified with biochemical and genetic methods. The enzyme-activity profiles were described for all strains, and the antimicrobial resistance and genetic determinants of antibiotic resistance were screened. During fermentation of cow’s milk, all three strains showed lower acid-forming activity but comparable proteolytic, antioxidant, and hypotensive activities in comparison with kefir starter culture.