SACCHAROMYCES AND NON-SACCHAROMYCES YEASTS

ETHANOL STRESS AND MEMBRANE FLUIDITY

Yeast cells undergo various stresses during the fermentation process, including that induced by ethanol, which can alter the fluidity of the cell membrane, compromise its integrity and increase its permeability.

The effect of ethanol on the growth of yeast strains was evaluated using selective media containing different concentrations of ethanol, while the effect on membrane fluidity was assessed by measuring generalized Laurdan polarization (GP) using a spectrofluorometer.

THE RESULTS OF THE STUDY

The results revealed high ethanol tolerance of S. cerevisiae strains up to a concentration of 14% (v/v), while non-Saccharomyces strains showed impaired growth when exposed to ethanol concentrations above 10% (v/v).

After 24 hours of exposure to 10% ethanol, both Saccharomyces and non-Saccharomyces strains showed decreased GP and increased membrane fluidity. However, at higher ethanol concentrations (14%), an increase in GP value was observed, suggesting stiffening of the cell membrane. In the case of S. cerevisiae strains, this phenomenon could be explained by the need to counteract the effects of ethanol, while for non-Saccharomyces strains it could be related to a significant decrease in cell viability.

 

This study highlights the different abilities of these strains to cope with ethanol stress in terms of growth and membrane fluidity. The results provide valuable insights for the development of resistant yeast strains that could lead to improved fermentation processes.

Documentation

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SIMTREA MEMBRANE FLUIDITY STUDY