Weak organic acid stress inhibits aromatic amino acid uptake by yeast, causing a strong influence of amino acid auxotrophies on the phenotypes of membrane transporter mutants.

The ability of yeasts to grow in the presence of weak organic acid preservatives is an important cause of food spoilage. Many of the determinants of acetate resistance in Saccharomyces cerevisiae differ from the determinants of resistance to the more lipophilic sorbate and benzoate. Interestingly, we show in this study that hypersensitivity to both acetate and sorbate results when the cells have auxotrophic requirements for aromatic amino acids.