Recent increases in the price of crude oil are providing impetus to develop alternative
sources of energy, including biofuels. Ethanologenic microorganisms such as
Saccharomyces cerevisiae are widely used by fermentation industries, and have been
used for many years to produce BioEthanol. However the productivity of this
microorganism is limited, in part because of its intolerance to the ethanol that it
generates. As ethanol levels increase during fermentation, yeast metabolic rate and
viability decrease which, in turn, compromises ethanol yield. Improving ethanol
tolerance of yeast should, therefore, lead to increased fermentation productivity. To
date, investigations on ethanol tolerance in yeast have mostly focused on analysis of
defective (ethanol-sensitive) mutants. This study presents work describing the
generation and characterisation of ethanol-tolerant mutants using an adaptive evolution
approach on mutagenised and non-mutagenised.populations of S. cerevisiae W303-1A.