Improvement of
ethanol stress tolerance in Saccharomyces cerevisiae through modulation of Ehrlich
pathway via overexpression of BAT2 gene
Vimanth S., Ningaraju T.M., Poornima R., Lakshminarayana Reddy C.N. and Chandrashekhara
K.N.
Res. J. Biotech.; Vol. 21(2); 62-70;
doi: https://doi.org/10.25303/212rjbt062070; (2026)
Abstract
Ethanol functions both as a primary product and a stressor in yeast fermentation,
particularly affecting Saccharomyces cerevisiae at high concentrations. Elevated
ethanol levels disrupt membrane integrity, enzyme activity and redox balance, reducing
yeast viability and fermentation efficiency. Enhancing ethanol tolerance is vital
for optimizing industrial fermentation processes. This study investigates the role
of the BAT2 gene, which encodes a cytosolic branched-chain amino acid aminotransferase
involved in the Ehrlich pathway- a metabolic route converting branched-chain amino
acids into fusel alcohols.
Overexpressing BAT2 significantly increases higher alcohol production and is correlated
with improved ethanol stress tolerance. These findings show that engineering the
Ehrlich pathway via BAT2 overexpression can strengthen yeast tolerance. This approach
offers a promising metabolic engineering strategy to develop yeast strains better
suited for industrial fermentation under ethanol stress conditions.
