Mìkrobìologìâ ì Bìotehnologìâ (Apr 2020)
BIOLOGICAL ACTIVITY OF LACTOBACILLI FROM DIFFERENT ECOLOGICAL NICHES OF THE SOUTHERN REGION OF UKRAINE
Abstract
Aim of the research was to study the antagonistic activity of lactobacilli isolated from different sources of the Southern region of Ukraine. Methods. The experiments used 13 strains of bacteria of the genus Lactobacillus isolated from different sources. The antagonistic activity of lactobacilli was determined by the well-diffusion method in the agar column using test cultures of pro- and eukaryotic microorganisms. Acid formation of the strains was evaluated by active and titrated acidity when cultured in milk. Results. All tested lactobacilli were active antagonists against gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis and Proteus vulgaris, as well against gram-positive Staphylococcus aureus and Staphylococcus saprophyticus. Lactobacilli showed less antagonistic activity against Bacillus subtilis and Klebsiella pneumonia. Lactobacilli isolated from meat (Lactobacillus spp. M2 and M3) were the most active antagonists. The active and titrated acidity of lactobacilli varied for different strains. Strain Lactobacillus sp. 175 isolated from child feces showed the highest titrated acidity. Using statistical methods (cluster analysis) made it possible to form clusters with high reliability by the level of antagonistic activity of investigated lactobacilli. The environmental factors have a definite influence on the formation of the general activity of lactobacilli strains, but the manifestation of each of the individual features is rather specific and depends on the capabilities of the certain microorganism. Conclusions. In the study of a number of properties that determine the antagonistic activity, five strains (Lactobacillus spp. О1, Б4, 175, М2 and М3) have been selected. They can be recommended for further researches for creation of probiotic preparation and functional foods.
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