Scientists have put genes from the burning bush plant into cover crops, such as camelina and pennycress, to produce acetyl-triacylglycerol (acetyl-TAG), the US Department of Energy reported on its official website.
Oil from the burning bush plant (Euonymus alatus) flows easily and stays liquid at relatively low temperatures, making it suitable for use in biofuel production.
The research team at Kansas State University used synthetic biology techniques to significantly increase the amount of acetyl-TAG oil in pennycress and camelina to near-pure levels, the 28 April US Department of Energy report said.
The breakthrough could lead to pennycress and camelina becoming a source for improved biodiesel, a report on the Kansas State University said on its website.
Most plant oils consist of triacylglycerols, molecules with three fatty acids linked to a glycerol backbone.
Acetyl-TAG found in the burning bush plant consists of only two fatty acids and a short acetate group. This different structure reduces the oil’s viscosity and lowers its freezing point, making it useful for a range of applications, including as an improved diesel drop-in replacement, the Department of Energy report said.
In their study, researchers engineered camelina and pennycress to produce acetyl-TAG in their seeds by introducing a gene from the burning bush that encoded the enzyme necessary for acetyl-TAG synthesis, the report said. This redirected the plants’ oil biosynthesis pathways. Additional modifications using genome editing techniques disrupted competing pathways and increased the availability of precursors, further boosting acetyl-TAG accumulation to nearly pure levels (up to 98% of all seed lipids). This result was achieved without significant effects on seed viability.
The low viscosity and cold temperature performance of acetyl-TAG makes it useful as a diesel replacement, according to the researchers.
“When we make biodiesel, we take regular vegetable oil and convert it into biodiesel using a chemical process,” Timothy Durrett, professor of biochemistry and molecular biophysics and one of the co-leads of the research team, said.
“The idea is that with these acetyl TAGs, the oil could be directly used as the fuel without any further chemical process needed.”
The team published its results in the Proceedings of the National Academy of Sciences and said its next step was to continue studying the modified camelina and pennycress plants to determine what other changes were taking place.
“This work highlights how advanced genetic engineering can optimise plants to produce valuable oils with tailored properties, opening the door to cost-effective biofuel production and other high-value industrial applications,” the US Department of Energy report said.
