Identification of new strains of lactic acid bacteria from south region of Kazakhstan

Abstract

The article describes the process of isolation and identification of lactic acid microorganisms derived from traditional homemade dairy products of the Southern region of Kazakhstan. During the study, 10 samples were selected. Of these, 5 separate isolates were selected: 2 koumiss isolates (Al-2, Al-3) and 3 ayran isolates (Al-1, Al-4, Al-5). A microscopic observation of koumiss isolates showed that they were cocci, isolated and collected in chains, and ayran isolates were large long rods. Spores were not formed. Bacteria were gram-positive facultative anaerobes. Colonies were convex with a solid edge, opaque and not pigmented. Optimum growth temperature was 37 °C. Identification was done by the MALDI-TOF method of mass spectrometry using the Microflex device based on the Maldi Biotyper database. Mass spectra were compared using Biotyper 3.0 RTC software. Based on the results, the Score value of the analyzed strains ranged from 2.096 to 2.449. As a result, it was found that isolates Al-2, Al-3 extracted from koumiss belong to the species Lactococcus lactis and isolates Al-1, Al-4, Al-5 extracted from ayran to Lactobacillus plantarum. The data obtained by us indicate that the results of microbiological identification are consistent. Antagonistic activity of cultures was studied by 2 test strains (S. aureus and E. Coli) using agar block method. The results showed that the lysis zone around the wells with Staphylococcus aureus culture was in the range from 12.00±1 mm to 18.00±1 mm, and Escherichia coli in the range from 13.00±1 mm to 17.00±1 mm. The isolates have an inhibitory effect on the indicator test strains: Staphylococcus aureus and Escherichia coli.