Improving acetic acid and furfural resistance of Saccharomyces
cerevisiae by regulating novel transcriptional factors revealed via
comparative transcriptome
Abstract
Acetic acid and furfural are the two prevalent inhibitors coexisting
with glucose and xylose in lignocellulosic hydrolysate. The
transcriptional regulations of S. cerevisiae in response to acetic acid
(Aa), furfural (Fur), and the mixture of acetic acid and furfural
(Aa_Fur) while fermenting with glucose and xylose were revealed. The
pathways classified as carbohydrate metabolism were significantly
enriched in response to Aa, while the pathways belonged to xenobiotics
biodegradation and metabolism were significantly enriched in response to
Fur. In addition to these pathways, some new pathways were activated in
response to Aa_Fur, i.e., cofactors and vitamins metabolism, and lipid
metabolism. Overexpression of Haa1p or Tye7p improved xylose consumption
rate by nearly 50%, while the ethanol yield enhanced by nearly 8%.
Further co-overexpression of Haa1p and Tye7 resulted in 59% increase in
xylose consumption rate and 12% increase in ethanol yield, revealing
the beneficial effects of Haa1p and Tye7p on improving the tolerance of
yeast to mixed fermentation inhibitors.