Branch-Chain Fatty Acid Production in Plants

The purpose of this project is to develop renewable, environmentally friendly lubricants such as motor oils that can meet today's high performance automobile and other engine specifications. The worldwide market for lubricants is about 36 Mt with that for motor oils being ~ 20 Mt. Plant oils can currently be used as automobile engine oils but only for short periods and do not meet automotive manufacturer's specifications due to the poor oxidative stability of the double bonds ofthe unsaturated fatty acids. Solutions to this problem include converting the double bonds commonly found in plant oils such as soybean oil into branch-chain groups. Such groups can have the adequate low temperature fluidity and lubricity + the needed very high oxidative stability. Various organisms including plants are capable of synthesizing and in some cases accumulating branch-chain groups in lipids such as seed oil triacylglycerol (TAG) but no such natural sources can produce these materials in high quantities or at low costs. The overall goal of the proposed research is to engineer plants to convert common unsaturated fatty acids that normally accumulate in seed oils into branch-chain groups and selectively transfer these moieties from membrane lipids into seed oil. This will convert normal plant oil fatty acids into forms with superior industrial lubricant properties; high oxidative stability with good flow properties over a wide range of temperatures. Various plant and microbial sources which naturally produce lubricant fatty acids have been identified and the genes needed will be cloned from such sources and genetically engineered into major oilseeds that can be produced in the US including soybeans. The overall goal of this research is to engineer plants to convert common unsaturated fatty acids that normally accumulate in seed oils (TAGs) into saturated branch-chain groups and selectively transfer these moieties into oil that can accumulate in plant tissues such as seeds. Plant oils containing high levels of branched chain fatty acids (BCF As) will be developed by transferring the natural ability of some organisms to make such fatty acids and oils into oilseed crops that can be economically produced in the US. The specific objectives are: 1) Cloning and characterization of genes encoding branch-chain fatty acid biosynthetic enzymes from source organisms. 2) Cloning and characterization of enzymes involved in the accumulation of branch-chain fatty acids from source organisms. 3) Characterization of model plants and oil seeds engineered with enzymes involved in the formation and accumulation of branch-chain fatty acids. This will convert normal plant oil fatty acids into forms with superior industrial lubricant properties; high oxidative stability with good flow properties over a wide range of temperatures.