Direct Evidence of Intracellular Alkalinization in Saccharomyces cerevisiae KNU5377 Exposed to Inorganic Sulfuric Acid

The toxicity of inorganic sulfuric acid as a stressor was characterized in Saccharomyces cerevisiae KNU5377. In this work, we examined physiological responses to low extracellular pH (pH∧ex) caused by inorganic H₂SO₄, which could not affect cell growth after pH was adjusted to an optimum with Trizma base. The major toxicity of sulfuric and was found to be reduction of environmental pH, resulting in stimulation of plasma membrane H+-ATPase, which in turn contributed to intracellular alkalinization.