Lower Viscosity Seed Oil has Potential as Direct-Use Biodiesel

At least four different types of DGAT enzymes have been identified in various species.

The Science

Vegetable oils are often suggested as an alternative fuel source, but their long-chain fatty acid-containing triacylglycerols cause coking and gum formation, precluding their direct use in diesel engines. However, seed tissues from the common ornamental shrub Burning Bush (Euonymus alatus) store high levels of an unusual type of triacylglycerol called acetyl glycerides (acTAGs). acTAGs have unique physical and chemical properties that render the oil 30% less viscous than conventional vegetable oils, suggesting potential for direct use as a biofuel source. Researchers at the DOE Great Lakes Bioenergy Research Center have discovered the specific gene that is responsible for synthesis of acTAGs in Euonymus. This gene was identified by a new low-cost DNA sequencing approach performed at the DOE Joint Genome Institute that greatly increases the probability of detecting rare genes. Transgenic Arabidopsis plants expressing the Euonymus acyltransferase produced acTAGs, resulting in highly modified seed oil. The expression of this gene and subsequent synthesis of these unusual oils in commercial oilseed crops offers potential for large-scale production as direct-use biodiesel.

The Impact

These results demonstrate the utility of deep transcriptional profiling with multiple tissues as a gene discovery strategy for low-abundance proteins. They also show that EaDAcT is the acetyltransferase necessary and sufficient for the production of acTAGs in Euonymus seeds, and that this activity can be introduced into the seeds of other plants, allowing the evaluation of these unusual TAGs for biofuel and other applications.


Durrett, T. P., D. D. McClosky, A. W. Tumaney, D. A. Elzinga, J. Ohlrogge, and M. Pollard. 2010. “A Distinct DGAT with sn-3 Acetyltransferase Activity that Synthesizes Unusual, Reduced-Viscosity Oils in Euonymus and Transgenic Seeds,” Proceedings of the National Academy of Sciences 107(20), 9464–9.