Microbial Small-Talk: Does Quorum Sensing Play a Role in Beer Fermentation?

Inter- and intraspecies communication between microorganisms is recognized to play an influential role across many relevant applications, such as bioethanol production, food preservation, bioremediation, wastewater treatment, and in the clinical environment. At high population densities, the accumulation of small hormone-like molecules in the extracellular environment has been demonstrated to play a role in transcriptional regulation of both prokaryotic and eukaryotic microorganisms. This mechanism enables independent cells, known as the quorum, to trigger coordinated, community-wide gene expression, increasing their prospect of survival in crowded and ever-changing conditions. This density-dependent phenomenon has been shown to influence community-wide behavioral factors, such as biofilm formation, virulence factor secretion, social motility, cellular adhesion, autolysis, secondary metabolite production, and nutrient uptake across a range of organisms. In Saccharomyces cerevisiae, aromatic alcohols 2-phenylethanol, tryptophol, and tyrosol have already been demonstrated to act as quorum sensing molecules under certain environmental conditions, such as low-nitrogen availability. This review discusses the underlying mechanisms of quorum sensing, with an emphasis on brewer's yeast, while offering insights into how cell density-dependent signaling could influence the commercial brewing industry.