Optimization and Production of acetyl-triacylglycerols for use as fuels, lubricants, and specialty chemicals

Societal concerns about dwindling fossil fuel reserves and climate change have increased the need to obtain fuel and chemical products from renewable sources. Plant oils have long been used as a source of energy and as feedstocks for industrial chemistry. This Phase I SBIR project is focused on producing high concentrations of acetyl-triacylglycerols (acTAGs) in a dedicated industrial oil seed crop, Camelina sativa. AcTAGs contain an acetate group instead of a longer-chain fatty acid at the sn-3 position of the glycerol backbone. This feature alters the physical and chemical properties of the oil, making it directly applicable for use as heavy (#4) diesel fuel. This means that biodiesel can be harvested directly from the plant, rather than having to be produced by chemically cleaving the plant oil to separate glycerol and fatty acids. In addition, this oil may have other uses typical of plant oils, for example as a feedstock for production of lubricants or surfactants. The Phase I work will revolve around the use of the Euonymus alatus Diacylglycerol Acetyltransferase (EaDAcT). This unique enzyme is responsible for the synthesis of the abundant acTAGs found as storage lipids in the seeds of the ornamental plant Euonymus alatus (Burning Bush). Members of our team have already demonstrated production of acTAGs in Arabidopis and Camelina expressing EaDAct. In this project, we will further raise these levels by increasing the flux of the glycerol-3-phosphate (G3P) backbone required for assembly of acTAGs. Additionally, we will enhance the oxidative stability of acTAG molecules by increasing the incorporation of oleic acid (18:1) at the sn-1 and -2 positions of the glycerol backbone, making the fuel more stable for long-term storage. The net result will be a new commercial source of biofuel useful in heavy diesel engines, such as locomotives or large generators, and a new type of oil with potential as a feedstock in many other applications. Key Words: Biofuel, Biodiesel, acetyl-triacylglycerols, Camelina, Diacylglycerol Acetyltransferase, oilseed, crop Summary: Production of biofuels is a national priority to reduce greenhouse gas emissions and promote energy independence. This project is optimizing the production of a novel biodiesel fuel produced in the crop plant Camelina sativa, generating a new crop for farmers and a new source of renewable fuels.