Fermentation Efficiency of Genetically Modified Yeasts in Grapes Must

Area of Science:

• * Molecular biology and yeast genetics
• * Biochemistry of fermentation processes

Background:

• * Yeast (Saccharomyces cerevisiae) face significant stress during winemaking due to high sugar and ethanol levels.
• * Efficient fermentation requires rapid adaptation, low-temperature performance, and balanced glucose/fructose utilization.
• * Msn2/4 proteins are key regulators of yeast stress response.

Purpose of the Study:

• * To investigate the impact of specific point mutations in Msn2/4 proteins on yeast fermentation.
• * To assess the effects of these mutations on fermentation rate, temperature tolerance, and sugar utilization.

Main Methods:

• * Creation of four yeast mutants with serine-to-alanine substitutions in Msn2/4 proteins.
• * Analysis of fermentation kinetics at various temperatures, particularly low temperatures (12 °C).
• * Evaluation of glucose and fructose utilization patterns.

Main Results:

• * The Msn4 S533A mutant (W_M4_533) significantly increased fermentation rate at 12 °C by reducing activation energy.
• * The Msn2 S582A mutant (S582A) showed similar, though less pronounced, improvements in fermentation rate.
• * The W_M4_533 mutant demonstrated improved balanced utilization of must hexoses (glucose and fructose).

Conclusions:

• * Genetic modification of Msn2/4 proteins offers a promising strategy to enhance alcoholic fermentation.
• * Targeted mutations can shorten fermentation times, especially at low temperatures, meeting important technological demands.
• * This approach can lead to more efficient and potentially higher-quality wine production.