SBIR Phase I: Development of an Engineered Yeast Strain for the Production of Butanol - a Second Generation Biofuel

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). This Small Business Innovation Research Phase I project describes the engineering of a novel recombinant Saccharomyces cerevisiae strain containing the butanol biosynthetic pathway. Currently, most butanol technology development focuses on the genetic manipulation of the Acetone-Butanol-Ethanol (ABE) fermentation microorganisms of the genus Clostridium. While several Clostridium species have the natural ability to make butanol via the ABE pathway, the amount of butanol produced is low, and therefore these strains would struggle to be commercially viable. To avoid this limitation, the genes involved in the butanol biosynthesis from Clostridium acetobutylicum were introduced into the yeast Sacharomyces cerevisiae using genetic engineering techniques. This simple eukaryote was chosen because of its robust nature in industrial fermentation and also because it is a genetically tractable organism. When combined with our work enabling yeast to digest and utilize cellulose as a feedstock, we expect to have generated a microbe capable of converting biomass into a next generation biofuel and industrial solvent. Much research and development has gone into the production of ethanol from biomass; although ethanol production is the most mature biofuel technology, other alcohol-based fuels, such as butanol, can be used as renewable replacements for gasoline. Butanol offers a number of benefits over ethanol including higher energy content; butanol can be used directly as a fuel in current vehicles without modification; butanol is less corrosive than ethanol and can be piped through the existing pipeline infrastructure. Butanol produced from petroleum is currently used as an industrial solvent or as feedstock for manufacturing plastics and has an existing market of several billion dollars worldwide. The current economic climate has forced the identification of new manufacturing processes that replace the use of petroleum. As a result, there is growing interest in fermentation of butanol from renewable resources. Through the 1940s, butanol was produced as a fermentation product by bacteria from the genus Clostridium. Due to economic considerations, manufacturing processes utilizing petroleum as the raw material replaced commercial scale fermentation. By utilizing non-food feedstock, the yeast strain that Arbor Fuel Inc will construct could play a significant role in reducing our country's reliance on petroleum and increase the utilization of renewable energy resources.