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

The broader impact and commercial potential of this Small Business Innovation Research Phase I project will be to enable the biochemical conversion of sugars into fatty acids that can be used to make fuels such as biodiesel. Xylome Corporation is using biotechnology to engineer a yeast platform that will produce fatty oils. This will facilitate conversion of existing biofuel and biomass byproduct streams into useful commercial fatty acids while reducing processing costs. The production of fatty acids will facilitate production of the initial downstream target which is biodiesel, but longer term, the technology could enhance production of higher value second-generation biofuels. Xylome?s proposed technology could produce approximately 1.2 million gallons of biodiesel/yr. worth about $4 million from the byproducts of a single 70 million gallon ethanol plant. Beyond sugars from byproduct streams of existing ethanol plants, Xylome?s technology platform could facilitate fatty acid production from cellulosic and hemicellulosic sugars serving as a feedstock for cellulosic biofuel production. The first objective of this Phase I research project is to enable lipid production during growth. The second will be to relieve cellular capacity constraints. The project will alter regulation of genes that limit production and introduce pathways that expand capacity. Yeasts, and fungi synthesize lipid when given excess carbon and limiting nitrogen, but low levels of lipid synthesis occurs during cell growth. Normally lipid only accumulates in cellular vacuoles after cell division has stopped. This requires extended cultivation times, and the amount of lipid that can be formed is constrained by the cell volume. The proposed approach will overexpress the enzymes for lipid synthesis so that the engineered cells will produce oil during growth while maintaining high levels of metabolic activity. New pathways will be introduced along with processes that will enable continuous lipid recovery. These modifications should enable a) lipid production in continuous high-density culture, thereby overcoming inherent low rates of lipid synthesis, and b) continuous separation of lipid, thereby alleviating the need for cell harvest, rupture and extraction.