Agriculture & Food, Volume 10, 2022

Abstract: The intake of probiotic microorganisms helps to restore and maintain the balance of the gastrointestinal microflora, which has a beneficial effect on the overall health of the individual. In order to be included in the composition of probiotic preparations or as starter cultures in the production of functional probiotic foods or beverages, newly isolated Lactobacillus strains must be identified and a number of probiotic properties must be demonstrated. Lactobacillus Pr2 isolated from spontaneously fermented yogurt was identified by physiological and biochemical (API 50 CHL) and molecular genetic (ARDRA-analysis and sequencing of the 16S rRNA gene) as a representative of the species Lactobacillus delbrueckii ssp. bulgaricus. The presence of some probiotic properties of Lactobacillus delbrueckii ssp. bulgaricus Pr2: resistance under model conditions of the gastrointestinal tract, antibiotic resistance profile, antimicrobial activity against pathogenic microorganisms and freeze-drying survival were examined. It was found that Lactobacillus delbrueckii ssp. bulgaricus Pr2 was highly sensitive to the effects of low pH values and the presence of enzymes (pepsin, pancreatin), to medium to high concentrations of bile salts in the medium (up to 1%), as well as to most of the antibiotics included in the study. However, the strain demonstrated high antimicrobial activity against pathogenic microorganisms and very good survival during the freeze- drying process. Lactobacillus delbrueckii ssp. bulgaricus Pr2 may be included in the composition of probiotics or as a starter culture for probiotic foods or beverages, but before that it is necessary to conduct additional research on the presence of other probiotic properties of the strain.