SBIR Phase II: Novel Bioprocess for Lipid Production from Industrial Byproducts

The broader impact/commercial potential of this Small Business Innovation Research Phase II Project is to produce economically the next generation of sustainable, renewable, clean burning, high energy density, transportation biofuels. The proposed technology once successfully developed will enable existing biofuel producers to reduce their costs while increasing the value and diversity of their byproducts. It will convert their industrial waste products into tailored fatty acids suitable for biodiesel. The technology will be compatible with and complementary to cellulosic ethanol producers, and it could potentially double the amount of biodiesel produced in the U.S. today. The 227 domestic ethanol plants range in size from less than 50 to more than 150 million gallons, and they have a total annual capacity of 15 billion gallons. Every gallon of ethanol also yields 1.9 pounds of soluble organics that must be evaporated or disposed. Xylome?s technology has the potential to convert half of this stream into biodiesel and to expand biodiesel production further with cellulosic feedstocks. By converting a larger fraction of the soluble cellulosic and hemicellulosic sugars along with fermentation byproducts, Xylome will increase the efficiency of existing ethanol plants and increase biofuel production. The objectives of this Phase II research are to increase the rates of production, modification and release of fatty acids from non-conventional lipogenic yeast. Fatty acids have much higher energy density than ethanol, but similar specific energy yields. Fermentation of organics to lipids can potentially occur with efficiencies equivalent to ethanol production. Lipids normally accumulate under nitrogen limiting conditions after replication has stopped. They are not excreted from the cells so recovery does not require distillation. In Phase I, Xylome scientists identified and over expressed genes that increase lipid accumulation by 1.2- to 2-fold under high nitrogen conditions. In Phase II, they will use mating, selection, screening and evolutionary adaptation to combine the best of these modifications. Xylome scientists have also targeted additional genes to modify and release fatty acids from the cell. Xylome plans to optimize lipid production both from a cellular level with metabolic engineering and from an engineering perspective through bioprocess design and cultivation conditions. Xylome will also engineer cells to use rapidly the complex mixture of soluble oligosaccharides, hemicellulosic sugars and fermentation byproducts. By applying advanced molecular techniques and synthetic biology, Xylome will open up new opportunities for sustainable biofuel production.