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Disruption of URA7 and GAL6 improves the ethanol tolerance and fermentation capacity of Saccharomyces cerevisiae
Author(s) -
Yazawa Hisashi,
Iwahashi Hitoshi,
Uemura Hiroshi
Publication year - 2007
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.1492
Subject(s) - yeast , saccharomyces cerevisiae , biology , ethanol , wild type , mutant , fermentation , strain (injury) , biochemistry , ethanol fermentation , gene , anatomy
Screening of the homozygous diploid yeast deletion pool of 4741 non‐essential genes identified two null mutants (Δ ura7 and Δ gal6 ) that grew faster than the wild‐type strain in medium containing 8% v/v ethanol. The survival rate of the gal6 disruptant in 10% ethanol was higher than that of the wild‐type strain. On the other hand, the glucose consumption rate of the ura7 disruptant was better than that of the wild‐type strain in buffer containing ethanol. Both disruptants were more resistant to zymolyase, a yeast lytic enzyme containing mainly β‐1,3‐glucanase, indicating that the integrity of the cell wall became more resistance to ethanol stress. The gal6 disruptant was also more resistant to Calcofluor white, but the ura7 disruptant was more sensitive to Calcofluor white than the wild‐type strain. Furthermore, the mutant strains had a higher content of oleic acid (C18 : 1) in the presence of ethanol compared to the wild‐type strain, suggesting that the disruptants cope with ethanol stress not only by modifying the cell wall integrity but also the membrane fluidity. When the cells were grown in medium containing 5% ethanol at 15 °C, the gal6 and ura7 disruptants showed 40% and 14% increases in the glucose consumption rate, respectively. Copyright © 2007 John Wiley & Sons, Ltd.