P46: Generation of ethanol and fusel alcohols from lignocellulosic material using Saccharomyces cerevisiae

Increased energy demands coupled with a finite supply of fossil fuels have caused sustainable energy generation to become a top priority on a global scale.  In order to completely eliminate the need for fossil fuels, we must improve first generation biofuel processes, such as creating ethanol by fermentation using glucose as the sole sugar source. We are using the brewer’s yeast Saccharomyces cerevisiae to create second generation biofuels.  S. cerevisiae has a natural tolereance to high concentrations of alcohol and is used extensively for fermentation.  Currently, fuel-grade ethanol is primarily produced from corn starch, which is rich in glucose.  This process creates a number of issues including cutting into a primary food supply for humans and livestock.  We have metabolically engineered a strain of S. cerevisiae that contains foreign genes allowing yeast to utilize alternate carbon sources like xylose and arabinose.  These alternate sugars are a component of lignocellulose a natural, abundant non-food polymer.  In addition to directed metabolic engineering, we intend to use in vitro evolution techniques to generate variants with increased pentose sugar metabolism. Our goal is to generate a strain capable of producing higher titers of ethanol and fusel alcohols.