Enzymatic hydrolysis of plant agricultural materials followed by cultivation of fodder yeasts Candida tropicalis and Saccharomyces cerevisiae

Relevance. Agro-food waste is a promising resource for the production of feed protein. Their processing using enzymatic hydrolysis and yeast cultivation allows obtaining microbial biomass with high nutritional value. This relevant area helps to solve the problem of feed protein deficiency in animal husbandry and sustainable use of resources in the context of environmental and economic challenges. Methods. Component analysis of raw materials (sunflower husk, brewer’s grain, lupine, beet pulp) was carried out according to standard methods, the raw materials were crushed, dried, subjected to enzymatic hydrolysis using enzyme preparations of the Ferment Group of Companies (Republic of Belarus) at optimal pH and temperature, with control of sugar yield, pH and conversion. Yeasts S. cerevisiae and C. tropicalis were cultivated on the obtained hydrolysates and the potential for using agro-waste was analyzed. Results. The maximum sugar yield was obtained during the hydrolysis of brewer’s grains (1.8%), for lupine — 1.7% (two peaks of sugar yield were observed at 2–4 and 7–9 hours), for pulp – 0.95% (peak at 4–5 hours). When cultivating S. cerevisiae and C. tropicalis on hydrolysates of brewer’s grains and lupine, the yeast grew more actively on brewer’s grains, reaching a protein content of 68.18% and 72.63% a. d. w. after drying, and using mainly the protein fractions of the original raw material dissolved in the hydrolysate during growth. The most promising hydrolysates are brewer’s grains and lupine, the optimal duration of enzymatic hydrolysis is 6–10 hours.