PSIX-14 - Influence of living yeast of the genus Rhodotorula against probiotic and pathogenic bacteria.
Wednesday, July 22, 2020
7:00 AM – 5:00 PM
Location: Poster Sessions
The aim of the research was to study the effect of live yeast Rhodotorula spp. (LYR) on the growth and development of microorganisms and microbial profiles in batch culture. A liquid medium was used to prepare the inoculum (20 g/L glucose, 20 g/L peptone, 10 g/L yeast extract). The study in vitro was a 3×5 factorial arrangement, including low (5.0) and high media pH (7.5) and temperature (from 20 to 39 ° C). The treatments were LYR with concentrations from 1·103 to 1·1011 CFU/ml. The bacteria were selected: Lactobacillus casei subsp. Rhamnosus ATCC 7469, Bifidobacterium breve ATCC 15701, E. coli ATCC 25922, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 14990. The analyses were carried out separately for each culture and LYR concentration by broth dilution. For incubation were used Saburo agar for LYR and differential-diagnostic media for each bacterial species. After incubation, there was a lack of growth of E. coli, S. aureus and S. epidermidis in LYR concentrations from 1·109 to 1·1011 CFU/ml at the temperature of 28±0.5 °С, while the number of yeast cells did not decrease. At the temperature above 32±0.5 °C there was a decrease in the amount of LYR by more than 1000-fold in the samples of all cultures. The presence of LYR in the medium led to an increase (p≤0.001) in the number of L. casei at pH 5.0 and temperature less than 30±0.5 °С. Unlike L. casei, the viability of the B. breve culture has decreased (P ≤0.05) by 200 times at pH 5.0, but has increased (p≤0.001) by more than 1000 times at pH 7.0. The optimal cultivation temperature was 36±0.5 °С. These results indicate the multidirectional effect of LYR on microorganisms in vitro. This work was supported by the Ministry of Science and Higher Education of Russia (topics GZ AAAA-A18-118021590136-7).