Yeast Cell Factories for Production of Biobutanol

Increasing oil demands and diminishing resources, as well as concerns over global warming, have stimulated interest in the biosynthesis of fuels from renewable sources. Biobutanols (1-butanol, 2- butanol and iso-butanol) have generated attention as alternative gasoline additives. Butanols are superior to ethanol as a fuel source due to their higher energy content and lower volatility, hygroscopicity and corrosiveness. In addition, they have sufficiently similar characteristics to gasoline to be compatible with existing engines and infrastructure.

While a natural pathway for 1-butanol production exists in the Clostridia species of bacteria, difficulties associated with cultivation and genetic manipulation of these bacteria have called for reconstruction of this pathway in more commonly used industrial microorganisms. The yeast Saccharomyces cerevisiae makes for an attractive host for 1-butanol production due to its robustness under industrial conditions, availability and abundance of information regarding its physiology, and a broad selection of tools available for its genetic manipulation. The goal of this project is therefore to use various synthetic biology and metabolic engineering tools to create efficient yeast cell factories for the production of 1-butanol. This includes introduction of a heterologous pathway for 1-butanol production into S. cerevisiae in combination with various modifications to acetyl-CoA metabolism to improve flux towards 1-butanol. We demonstrate that such manipulations significantly increase 1-butanol production in yeast.