Cytosolic peroxiredoxin Tsa1 influences acetic acid metabolism and pH homeostasis in wine yeasts

Abstract

Acetic acid is a key metabolite in yeast fermentation, influencing wine quality through its role in volatile acidity. In Saccharomyces cerevisiae, acetic acid production involves aldehyde dehydrogenases, primarily Ald6 during fermentation and Ald4 under respiration. However, the regulatory mechanisms of these enzymes throughout fermentation and how they differ in commonly used strains remain partially unclear. This study explores the cytosolic peroxiredoxin Tsa1 as a novel regulator of acetic acid metabolism. TSA1 gene deletion revealed strain-dependent effects on acetic acid metabolism and tolerance, showing reduced production and enhanced consumption in laboratory media. Under respiration, Ald4-driven acetic acid production, which raises extracellular pH, was mitigated by the absence of Tsa1. During wine fermentation, TSA1 deletion decreased the initial acetic acid surge by downregulating ALD6 transcription and enzymatic activity. These findings position Tsa1 as a metabolic regulator and a potential target for modulating acetic acid levels to manage volatile acidity and wine quality.