Scientific journal NRU ITMO
Series "Processes and Food Production Equipment"
Registration certificate ЭЛ № ФС 77 – 55245 - 04.09.2013
registered by the Federal Inspectorate Service for Communication, Information Technologies and Communication Media

2020 (published: 23.03.2020)

Number 1(43)

Home > Issue > Morphometric study of Saccharomyces cerevisiae yeast cells as a method for evaluating their physiological state

UDC 663.15

Morphometric study of Saccharomyces cerevisiae yeast cells as a method for evaluating their physiological state

Kuznetsova T.A., Ivanchenko O. B.

The morphological state of Saccharomyces cerevisiae yeast cells was assessed when they were cultured under various stressful conditions in order to improve a set of methods that allowed us to evaluate the physiological state of yeast cells in the technological process. The оbjects of study are strains of bottom-fermented brewing yeast p. Saccharomyces W-34/70 and S-189 (Saflager, Belgium). We studied the state of the yeast population under the toxic effects of ethanol by the intensity of CO2 emission, and also conducted a microscopic study to identify cells various physiological states (age, ultrastructure, dead, weakened, and living). The activity of the yeast population was determined by the volume of CO2 released by the express method using syringes. A morphometric study of yeast cells was carried out by microscopy of intravital preparations; measurements were carried out using Levenguk microphotography analysis software tools. The number of cells in the yeast suspension was determined by counting in a Goryaev chamber; preparations were stained with blue methylene to detect dead and weakened cells. It was found that an increase in the concentration of ethanol in the yeast suspension leads to a decrease in the formationof CO2, which is explained by an increase in the proportion of dead cells in the population of yeast cells. At a concentration of 5% ethanol the proportion of dead cells in the test samples reaches 13%, and at 20% it reaches 89% for strain W-34/70, and 91% for S-189. An increase in the toxic effect of alcohol leads to a decrease in the size of living cells (S projection, μm2) by 30% (strain S-189), by 28% (strain W-34/70), which is explained by plasmolysis. The studied factors also lead to a change in the shape of the cells, it becomes round, which allows us to determine the shape factor of the cells. Morphophysiological parameters of the cells of the yeast population, which are diagnostic features, such as shape, size, and ultrastructure of the cells are informative for predicting the state of the yeast population in the process.
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Keywords: microbiological production; morphophysiological study; ethanol stress; yeast; Saccharomyces cerevisiae; fermentation rate

DOI 10.17586/2310-1164-2020-10-1-39-46

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