This article describes the effect of organic acids and ultrasound on the physiological and biochemical properties of yeast, which was used to obtain biologically active peptides. The research featured brewer’s yeast S. cerevisiae W-34/70 cultivated in 11% beer wort. A mix of Krebs cycle acids served as an activator. It included succinic, malic, fumaric, citric, and oxaloacetic acids (1:1:1:1:1). The concentration of the Krebs cycle acids was 1 × 10⁻¹⁰ M/L at 1% to the suspension volume. The ultrasound treatment had an intensity of 10 W/m² and lasted 3–10 min. The combined effect increased the fermentation activity of the yeast by 98%. The activity of individual biocatalysts of constructive and energy metabolism rose by 108–330%, while that of proteolysis enzymes increased by 15% in comparison with the samples exposed to individual factors. The stimulation increased the rate of amine nitrogen consumption by the yeast. The amount of accumulated amino acids was larger by 80% than in the control, and that of protein larger by 7%. The maximal content of the synthesized protein was reached 1–2 h earlier. The combination of chemical and physical factors intensified the biosynthesis of protein and its intermediates during yeast processing, thus facilitating the subsequent extraction of biologically valuable components.

Various methods are used to prevent the deterioration of the biotechnological properties of brewer’s yeast during storage. This paper studied the use of artificial neural networks for the mathematical modeling of correcting the biosynthetic activity of brewer’s seed yeast of the C34 race during storage with natural minerals. The input parameters for the artificial neural networks were the suspending medium (water, beer wort, or young beer); the type of the zeolite-containing tuff from Siberian deposits; the tuff content (0.5–4% of the total volume of the suspension); and the duration of storage (3 days). The output parameters were the number of yeast cells with glycogen, budding cells, and dead cells. In the yeast stored with tuffs, the number of budding cells increased by 1.2–2.5 times, and the number of cells with glycogen increased by 9–190% compared to the control sample (without tuff). The presence of kholinskiy zeolite and shivyrtuin tuffs resulted in a significant effect. The artificial neural networks were required for solving the regression tasks and predicting the output parameters based on the input parameters. Four networks were created: ANN1 (mean relative error = 4.869%) modeled the values of all the output parameters; ANN2 (MRE = 1.8381%) modeled the number of cells with glycogen; ANN3 (MRE = 6.2905%) modeled the number of budding cells; and ANN4 (MRE = 4.2191%) modeled the number of dead cells. The optimal parameters for yeast storage were then determined. As a result, the possibility of using ANNs for mathematical modeling of undesired deviations in the physiological parameters of brewer’s seed yeast during storage with natural minerals was proven.

Yeast cultures with advanced metabolic indicators improve various industrial biotechnological processes. New sources of biostimulators involve mainly natural resources, e.g., Taraxacum officinale Wigg. or Trifolium pratense L., as well as non-destructive extraction methods, e.g., supercritical fluid extraction (SCFE). This research featured the effect of CO2 extracts of T. officinale and T. pratense on the enzymatic and physiological profiles of yeast culture. The experiment involved CO2 extracts of T. officinale and T. pratense obtained by SCFE at 8.0–20.0 MPa and 40°C, as well as industrial brewer’s yeast. The method of gas chromatography made it possible to reveal the chemical composition of the extracts while the Warburg method revealed the fermentation activity of the yeast. The rational parameters of SCFE for T. officinale included a working pressure of 15.0 MPa while for T. pratense it was 8.0–15.0 MPa. The separate fractions of CO2 extracts obtained with SCFE differed in many aspects. The appearance varied from liquid to waxy. The refractive index correlated with the working pressure. The chemical composition was represented by different mixes of hydrocarbons, phenolic compounds, fatty acids, ketones, aldehydes, and alcohols. The bioactive potential demonstrated antibacterial, antioxidant, and other properties. The analysis involved the chemical composition of the CO2 extracts during longterm storage based on spectrograms and chemical composition. It showed a decrease in the concentration and transformation of polyphenols, flavonoids, and other essential oil components. The microbiological profile of the CO2 extracts was as follows: on storage day 30 at 20–24°C, they contained gram-negative bacteria. However, no microflora was detected when the storage conditions were 2–4°C in the dark. The initial extracts were also microflora-free. When treated with aqueous solutions of CO2 extracts of T. officinale and T. pratense for 20–30 min in an amount of 0.2–2.0% biomass volume, the yeast increased their fermentation activity by an average of 220% while the dead cell count went d own. In this research, the CO2 extracts of T. officinale and T. pratense demonstrated good prospects as industrial yeast biostimulators.

Введение. Интенсификация процесса ферментации среды напрямую связана с активностью дрожжей. Зерновые отруби ‒ доступный источник биологически ценных для дрожжей веществ (азотистых, минеральных, витаминов), извлечение которых возможно различными приемами.Цель.Изучить влияние экстрактов, полученных обработкой отрубей (пшеничных, ржаных, овсяных) ультразвуком (УЗ) и ферментными препаратами, на бродильную активность пивных дрожжей.Материалы и методы. Объекты – экстракты отрубей, производственные пивные дрожжи. Параметры обработки водно-отрубных суспензий УЗ: мощность 30‒90 % от полной, длительность от 1 до 7 минут; ферментными препаратами (Termamyl 60 L, Ultraflo XL, Alkalase, Ondea pro) ‒ температура 55 °С, время от 40 до 120 минут.Результаты.Выявлен максимальный выход сухих веществ и азота аминокислот через 5 минут озвучания при мощности УЗ 70 % в ржаном экстракте. Большую эффективность по содержанию аминного азота в экстрактах обеспечили препараты Alkalase (в 1,4‒2 раза по отношению к контролю ‒ отруби без обработки), Ultraflo XL (в 1,1‒2,5 раза), Ondea pro (в 1,2‒2,3 раза), по редуцирующим веществам ‒ Termamyl (в 1,2‒3 раза), Ondea pro (в 1,1‒3,8 раза), Ultraflo XL (в 1,2‒1,7 раза). При любом способе получения экстрактов по абсолютным значениям исследуемых показателей преимущество у ржаных и пшеничных, по величине прироста по отношению к контролю – у овсяных экстрактов. Выдержка дрожжей с УЗ экстрактами (ржаным/овсяным) обеспечила через 20 минут рост бродильной активности в среднем на 40 % в сравнении с пшеничным экстрактом, с экстрактами после воздействия Termamyl и Ondea pro ‒ на 170 и 260 % от контроля.Выводы. Использование отрубных экстрактов повышает биокаталитическую активность дрожжей, что в дальнейшем интенсифицирует размножение культуры, азотистый обмен с целью получения биоактивных пептидов.