Plant Water Relations

Yeasts, especially \textit{Saccharomyces cerevisiae}, perform fermentation to produce ethanol (alcohol) and carbon dioxide from sugars under anaerobic conditions. However, alcohol at high concentrations becomes toxic to yeast cells themselves. When the concentration of ethanol exceeds 13%, it disrupts the integrity of the yeast cell membrane, denatures proteins, and interferes with vital metabolic processes. This self-generated ethanol buildup effectively poisons the yeast, leading to cell death, which is why industrial ethanol production rarely goes beyond this threshold without using ethanol-tolerant strains or distillation processes.