Ecological, biological and biotechnological aspects of Saccharomyces Cerevisiae biomass production

Baker's yeast Saccharomyces Cerevisiae (S. cerevisiae), belonging to the Ascomycota yeast type and being facultatively anaerobic, plays a key role in ecology, fundamental and evolutionary biology, biotechnology and industrial fermentations, in particular, in the production of fermented food and beverages. Saccharomyces Cerevisiae (S. cerevisiae) grows on substrates with a high sugar content and is an important ingredient in flour bakery and confectionery products. In yeast, glucose metabolism is carried out by oxidation or fermentation, in the first case, this leads to cell growth, and in the second – to the formation of ethanol. A high concentration of glucose or a low concentration of oxygen in the nutrient medium stimulates the Crabtree effect, which inhibits cell growth and increases the formation of ethanol. The article reveals the fundamental and applied biology of baker's yeast Saccharomyces Cerevisiae and reveals the technological methods of enriching beet molasses with nutrients in order to increase the yield of biomass. It is shown that the successful commercial production of baking yeast Saccharomyces Cerevisiae is determined by biological (Saccharomyces Cerevisiae yeast strain with good breeding indicators; crop size, etc.) and technological (molasses quality: nature, composition, and concentration of substrate; cheap, suitable for cultivation carbon source; easily controlled cultivation process to obtain the most viable biomass, physico-chemical conditions of cultivation, primarily temperature, pH; cultivation period; development of the canning process, etc.) condıtıons. In industrial production, Saccharomyces Cerevisiae baker's yeast is obtained either from collection centres at the initial stages, or its own strains are isolated and cultivated, and subsequently, cultures are maintained, ensuring consistency of quality and productivity. The breeding characteristics of baker's yeast are: the ability to adapt to changing cultivation conditions, because the composition of molasses has high variability; the efficiency of respiratory metabolism during yeast production, which determines the yield of biomass; biomass production; cell growth rate; the ability to ferment; ability to quickly convert carbohydrates into CO۲; ethanol production; dehydration; the volume of the final product, structure, colour (carbohydrates, amino acids); stress resistance to environmental conditions, in particular, to cold stress; shelf life (acids, glycerine). Today, as shown in the article, technological methods for enriching beet molasses with nutrients have different solutions. Molasses is enriched with cereals (cottonseed, cereal germs, legumes, peanut fodder cake), plant hormones, specific growth factors, animal products (milk, whey, animal waste), ammonium sulphate, malt (expensive), aqueous ammonia, ammonium salts. The enrichment of molasses with nutrients based on the use of cereals, glucose syrup obtained from corn, date syrup, whey, cassava, forestry, and agricultural waste has commercial potential, since these approaches do not require special processing requirements and provide low production costs (exception: forestry waste). In the technology of Saccharomyces Cerevisiae biomass production, a population of diploid cells is used, since compared with haploid cells they are genetically more stable, characterized by faster and more active metabolism, and larger sizes.

کلیدواژه ها:

Saccharomyces cerevisiae ، Biochemistry of baker's yeast ، Carbon metabolism ، cultivation ، Molasses ، Biomass ، Ecology