Acetic acid induces strain-specific metabolic adaptation of Saccharomyces cerevisiae during pH stress

ATCC 9804 and ATCC 13,007 under aerobic or static cultivation at pH 3.0. 10 mM AA caused only minor physiological changes, whereas 20 mM AA stimulated respiratory activity, increasing oxygen consumption up to 3.0-fold. In contrast, 50 mM AA markedly impaired metabolism, reducing biomass formation ∼ 110.0-fold under static cultivation, decreasing CO₂ production ∼ 250-fold, and suppressing glucose utilization and ethanol production. ATCC 9804 maintained higher respiratory capacity, acetate utilization, biomass carbon recovery, whereas ATCC 13,007 exhibited pronounced metabolic exhaustion under static cultivation. The results demonstrate that maintenance of respiratory capacity and efficient carbon flux allocation are key determinants of AA tolerance at pH 3.0. These findings provide new insights into the metabolic mechanisms underlying weak organic acid adaptation and offer framework for engineering robust industrial yeast strains.