2-58: Effects of S-adenosyl-l-methionine on membrane components and ethanol tolerance in Saccharomyces cerevisiae

Ethanol tolerance is an essential factor of metabolic engineering for bioethanol production because ethanol inhibits the growth, fermentation, and viability of cell. However, the research to improve ethanol tolerance of bioethanol producing microorganism have not been effectively proceeded because the cellular toxicity of ethanol and its mechanism have been barely known. We postulated that ethanol effect on membrane fluidity is major factor of cellular toxicity by ethanol. S-adenosyl-L-methionine(SAM), as a universal methyl donor, is consumed in biosynthetic pathway of ergosterol and phosphatidylcholine which are key components in membrane. We discovered SAM accumulating strain of Saccharomyces cerevisiae showed improved ethanol tolerance and its composition of ergosterol and phosphatidylcholine decreased. We concluded that SAM effects on membrane can improve the ethanol tolerance of cell by modification of membrane fluidity.