Saccharomyces cerevisiae is currently the microorganism of choice for industrial production of ethanol. Whether this will remain the case depends to a large extent on the success of yeast metabolic engineering. A major challenge in this respect is the rather narrow substrate range of wild-type S. cerevisiae strains. This limitation becomes especially relevant once industrial ethanol production moves from starch- and sucrose-rich feedstocks to lignocellulosic biomass.

This presentation gives an overview of the research of metabolic engineering S. cerevisiae for the fermentation of the sugars D-xylose and L-arabinose at the Delft University of Technology. These pentoses are important constituents of plant biomass hydrolysates and their efficient and fast fermentation to ethanol is a prerequisite for economically feasible fuel ethanol production from such feedstocks. Redox contraints appear to be a major factor in the formulation of succesful strategies for pentose fermentation. This presentation underlines the importance of the integration of metabolic engineering, in vivo evolution (evolutionary engineering) and fermentation process design.