12/19/2014

Field Production of Novel Plant Oils in Camelina

Summary

Some plants synthesize acetyl-triacylglycerols (acetyl-TAGs), some of which are suitable as ‘drop-in’ biodiesel. A diacylglycerol acetyltransferase from Euonymus alatus, EaDAcT, synthesizes such acetyl-TAGs when expressed in Arabidopsis, Camelina, and soybean. Compared to most vegetable oils, acetyl-TAGs have reduced viscosity and improved cold temperature properties that confer advantages in applications as biodegradable lubricants, food emulsifiers, plasticizers, and ‘drop-in’ fuels for some diesel engines. Previously, researchers in the Department of Energy’s Great Lakes Bioenergy Research Center (GLBRC) engineered a Camelina line producing high levels of oleic to express the EaDAcT gene to produce acetyl-TAG oils with fatty acid compositions and physiochemical properties complementary to wild-type acetyl-TAG. In field-grown engineered Camelina, the acetyl-TAGs accumulated to 70 mol% of seed TAG and had minor or no effect on seed weight, oil content, harvest index, and seed yield. The total moles of TAG increased up to 27%, reflecting the ability to synthesize more acetyl-TAG from the same supply of long-chain fatty acid. The crystallization temperature of high-oleic acetyl-TAG was reduced by 30? C compared to control TAG. The viscosity of high-oleic acetyl-TAG was 27% lower than TAG from the high-oleic control, and the caloric content was reduced by 5%. Field production of T4 and T5 transgenic plants yielded over 250 kg seeds for oil extraction and analysis. These results demonstrate that high-oleic Camelina lines can be engineered to produce desirable oils for ‘drop-in’ biodiesel and that establishing crop production of Camelina acetyl-TAG will enable sufficient quantities of acetyl-TAG to be produced for further agronomic and commercial development.

References

Liu, J., H. Tjellstrom, K. McGlew, V. Shaw, A. Rice, J. Simpson, D. Kosma, W. Ma, W. Yang, M. Strawsine, E. Cahoon, T. P. Durrett, and J. Ohlrogge. 2015 “Field Production, Purification, and Analysis of High-Oleic Acetyl-Triacylglyceros from Transgenic Camelina sativa,” Industrial Crops and Products 65, 259-68. DOI: 10.1016/j.indcrop.2014.11.019.