Metabolic opportunities offered by wild-type and engineered Saccharomyces cerevisiae strains for biofuels production

Human society has always been dependent on biomass-derived carbonand energy for nutrition and survival. Recently, we have also become dependent on petroleum-derived carbon and energy for commodity chemicals and fuels. However, the nonrenewable nature of petroleum stands in stark contrast to the renewable carbon and energy present in biomass. Thus, there is an increasing demand to develop and implement strategies for production of commodity chemicals and fuels from biomass instead of petroleum. One of the main impediment to the massive production of biofules is the lack of an efficient, high-yielding, commercially feasible process. Thus, in order for a bio-based process to compete with existing (petroleum-based) processes, the target chemical must be produced at high yield, titer and productivity. This Ph.D. project was aimed at developing and optimizing yeast strains able to produce alcohols and organic acids of industrial interest through a metabolic engineering approach. The potentialities linked to yeast natural metabolic versatility were also evaluated with respect to the production of the different compounds of interest. Starting from this base-line, yeast capability has been improved by the expression of endogenous and eterologous activity.