Engineering the pentose phosphate pathway in Saccharomyces cerevisiae using an evolutionary engineering based strategy.

An evolutionary engineering strategy based on long-term batch culture on gluconate was used to selected S. cerevisiae strains that had a greater gluconate consumption capacity after 70, 180 and 240 generations. During wine fermentation, these evolved strains produced similar amounts of ethanol as the parental strain (EC1118) but displayed completely novel phenotypes, including higher fermentation rates, lower nitrogen requirements, lower levels of acetate production and enhanced production of aroma compounds. Carbon flux and transcripomic analysis of one of these strains, ECA5, showed a greater flux through the PP pathway consistent with the observed increased expression of GND1 and TKL1 genes. The expression of genes associated with nitrogen metabolism, the Ehrlich pathway, proton homeostasis and glycolysis was stronger than in the parental strain EC1118, whereas genes involved in stress response and respiration were down-regulated.