The future of bioethanol

Yeasts have been domesticated by mankind before horses. One yeast species in particular, Saccharomyces cerevisiae, may be considered the world’s premier microorganism – responsible for the production of many industrial commodities, including baked foods, alcoholic beverages, biofuels and biopharmaceuticals. After the mastering of alcoholic fermentation for millennia, yeasts (mainly S. cerevisiae) have become the protagonist of one of the most important biotechnological industries worldwide: the production of fuel alcohol or bioethanol. Bioethanol can significantly decarbonise our future energy needs, since its production can alleviate the negative impacts of greenhouse gas emissions from fossil fuels, and thus constrain global climate change. Production of bioethanol is obtained from the fermentation of sugars derived from sugarcane and maize as conducted primarily in Brazil and the US, respectively. Although these are considered mature industries, there is still much room for improvement, particularly with regard to enhancement of yeast fermentation performance. This chapter will initially present some important yeast and fermentation challenges to be overcome in this industry, both in firstand second-generation biofuel production. Some important advances obtained in recent years are also discussed that have improved bioethanol production. This chapter will finally present and discuss some opportunities, in the scope of yeast metabolic engineering and synthetic biology, which will likely prove very beneficial for industrial bioethanol processes in the future.