Enzyme complexes for activating yeast generation and ethanol fermentation
2022
Liubov V. Rimareva | Elena M. Serba | Marina B. Overchenko | Nataliya V. Shelekhova | Nadezhda I. Ignatova | Anzhelika A. Pavlova
Introduction. Recent studies have shown the benefits of phytolytic enzymes to prepare grain wort in ethanol production. However, there is a lack of data on the effect of phytases and their amount on the conversion of grain polymers, the ionic composition of wort and mash, and the efficiency of yeast generation and ethanol fermentation. Study objects and methods. Wheat and corn wort samples were treated with a complex of hydrolases, including phytases. Capillary electrophoresis determined the ionic composition of wort and mash. Gas chromatography measured the content of volatile metabolites. Results and discussion. The key enzymes were phytases and proteases. They improved the conversion of grain polymers and stimulated the growth and metabolism of yeast cells. Their synergism enriched the wort with assimilable nitrogen, phosphorus, and other valuable minerals. In addition, it intensified the growth of the Saccharomyces cerevisiae yeast, increased the rate of carbohydrate consumption, and reduced the formation of side metabolites 1.7–1.9 times, mainly due to higher and aromatic alcohols. The concentration of phosphates remained practically unchanged during the fermentation of grain wort treated with phytases. However, by the end of fermentation, it was 2.4–5.1 times higher than in the mash samples without phytolytic treatment. Finally, we identified a complex of enzymes and optimal amounts of phytases that have a stimulating effect on ethanol fermentation. Conclusion. Phytases, whether used individually or together with proteases, enriched grain wort with soluble macro- and microelements, improved yeast metabolism, directed ethanol synthesis, and decreased the formation of fermentation by-products.
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