Flocculation in Saccharomyces cerevisiae: a review

Area of Science:

• * Microbiology
• * Molecular Biology
• * Biotechnology

Background:

• * Yeast flocculation is a crucial trait historically used for cell separation in brewing.
• * Understanding flocculation's regulation is key to optimizing yeast performance in various industrial processes.
• * Yeast cell aggregation in flocs represents a form of social behavior with survival advantages.

Purpose of the Study:

• * To critically review factors influencing yeast flocculation.
• * To update knowledge on the metabolic control of flocculation onset and loss.
• * To highlight the broad applicability of flocculent yeast strains.

Main Methods:

• * Comprehensive literature review and critical discussion of existing research.
• * Analysis of factors affecting yeast flocculation: chemical medium characteristics (pH, ions), fermentation conditions (oxygen, sugars, temperature, ethanol), and gene expression (FLO genes).
• * Examination of metabolic control mechanisms and genetic regulation of flocculation.

Main Results:

• * Yeast flocculation is significantly influenced by pH, bivalent ions, oxygen, sugars, growth temperature, and ethanol concentration.
• * Expression of specific genes (e.g., FLO1, FLO5, FLO8) plays a vital role in regulating flocculation.
• * Flocculation offers advantages in brewing, winemaking, bio-ethanol production, heterologous protein expression, and heavy metal bioremediation.

Conclusions:

• * Flocculent yeast strains have diverse industrial and biotechnological applications.
• * Further research into metabolic and genetic control can optimize yeast flocculation for various uses.
• * Yeast flocculation exemplifies social behavior, aiding survival and protection in challenging environments.