Search for new yeast strains to improve the feed base

Currently, yeast cultures are used in a large number of industry areas. The use of microbial biomass as a protein, probiotic, enzyme additive requires a comprehensive study of its composition, digestibility, digestibility, toxicity testing, not only of living cells, but also of their metabolic products. The aim of the work was to determine the potential of isolated microorganisms for the development of biotechnological products of microbial synthesis. The result of the studies were 2,356 strains of bacteria and fungi isolated from the gastrointestinal tract of agricultural animals. Of these, 1,641 were classified as opportunistic bacteria and excluded from the study. Of these, 12 isolates of yeast of the Saccharomyces class were selected for further studies after the toxicity was determined. In our studies, isolated yeast isolates had the ability to ferment glucose, dextrose, sucrose and mannose in more than 83% of samples; fructose, inulin, esculin and citrate - more than 67%; galactose, raffinose and sorbose more than 50%. All the studied isolates were tested for the quantitative content of protein in the cells. Fluctuations in crude protein ranged from 37.14% to 46.05%, which suggests the possibility of increasing its content when enriching the growth medium during cultivation. The highest levels of lysine were observed in samples Sf 7, Sf 28, Cr 11 (4.91, 5.11, 5.07 g/100 g of SP, respectively), methionine in samples Sr 9, Cr 2, Cr 32 (4.83, 6.78, 5.42 g/100 g of SP, respectively), and threonine in samples Sf 28, Sf 45, Cr 11 (6,08, 6,22, 5,71 g/ 100 g SP respectively).High enzymatic activity, high-grade amino acid composition, intermediate position between vegetable and animal protein in further research makes it possible to use the isolated microorganisms as a feed product in animal husbandry.