Husker-led team exploiting oilseeds’ potential in biofuels, bioproducts

A University of Nebraska–Lincoln researcher is leading a team working to unlock the full potential of two oilseeds that may help meet the escalating demand for renewable fuels, industrial chemicals and other bioproducts. The team will produce genetically enhanced oilseeds, establish the “rules” of oilseeds’ metabolic circuitry and develop synthetic biology tools for crop improvement that could help scientists across the country.

With a five-year, $12.8 million grant from the U.S. Department of Energy, Nebraska biochemist Edgar Cahoon will lead an interdisciplinary team representing eight institutions in exploring how camelina and pennycress, which contain the fatty acids necessary for producing biofuels and biomaterials, could help replace petroleum-based products and mitigate the effects of climate change. The project will pave the way for wider use of oilseeds in environmentally friendly and sustainable applications.

“Looking to the future, we think that cars will be electrified, but there will still be demand for liquid fuels for jets, tractor-trailers and heavy equipment. We’re looking for renewable sources for these types of liquid fuels,” said Cahoon, George W. Holmes Professor of biochemistry. “And those feedstocks can also be used for chemical applications, like making bioplastics and lubricants with better properties.”

The grant reflects Nebraska’s research strengths in plant sciences and biofuels while highlighting the ability of university research to help local producers and boost the state’s economy.

“This project holds enormous potential to expand the development, production and use of biofuels and advanced biomaterials,” said Mike Boehm, NU vice president and Harlan Vice Chancellor for the Institute of Agriculture and Natural Resources. “Just as importantly, development of new oilseed crops represents an opportunity for Nebraska farmers to diversify their operations and expand into new markets. This is exactly the kind of meaningful work we strive for as a land-grant university.”

The award also underscores Cahoon’s leadership in the plant sciences field.

“Ed has long been a national leader in this area, and this grant underscores not just his research expertise, but his ability to unite an interdisciplinary team toward a common goal,” said Bob Wilhelm, vice chancellor for research and economic development. “The team’s work will help tackle some of the world’s most critical challenges, like climate resilience and energy security.”

The project focuses on pennycress and camelina, members of the mustard, or Brassicaceae, family, because these plants do not compete with food crops — an important consideration when the global population is expected to reach nearly 10 billion by 2050. The oilseeds are also resilient, with the ability to grow as winter cover crops or on marginal or underused land.

Pennycress and camelina oilseeds aren’t ideal precursors for bioproducts yet. Their oil content is suboptimal — roughly 30% of their seed weight is oil, falling short of the 40%-plus target — and they contain a less-than-ideal mixture of fatty acids. Cahoon’s team aims to change both characteristics.

“We’re trying to make not just more oil per seed, but oil of a more defined chemical structure to make biomaterials with more uniform and consistent properties,” said Cahoon, director of the university’s Center for Plant Science Innovation.

The project’s research component focuses on a cell part called the plastid, which in oilseeds functions as a “biofactory” that controls the amount and types of fatty acids produced. Cahoon’s team will explore the inner workings of the plastid, with a focus on how multiple enzymes work in concert to dictate fatty acid production — an approach that has been overlooked to date. That approach will rely on advanced chemical analysis and bioinformatics tools developed by team members.

The researchers are also taking a closer look at an oilseed plant called Cuphea, which Cahoon characterizes as “extreme” because it produces exceptionally high levels of a single type of fatty acid, which has a medium-length carbon chain. Both attributes are desirable: Fatty acid homogeneity is useful because specialty materials like nylon require a uniform starting material. Medium-chain fatty acids are ideal for jet fuels and renewable diesel because producers can sidestep the energy-intensive process of breaking up unusable long-chain fatty acids.

“We want to learn from the extremes like Cuphea, then take that knowledge and overlay it on the typical oilseeds, like pennycress and camelina,” Cahoon said.

To conduct the research, the team will use modeling tools developed by collaborator Jerome Fox of the University of Colorado Boulder. The team will take those tools, originally developed to investigate fatty acid synthesis in E. coli, and apply them to plants.

Cahoon’s team will also design synthetic biology tools that enable the rapid, predictable genetic modification of plants. The researchers will specifically tap into emerging CRISPR gene-editing technology to develop sophisticated methods for delivering genes into specific regions of the plant genome and for precisely controlling gene expression.

By applying CRISPR technology in plants, Cahoon’s team is taking a major step forward. While similar methods are frequently used in the genetic engineering of single-celled microbial species, it’s more challenging to make the leap to biologically complex plants.

The team will use those tools, in tandem with its research findings, to produce genetically enhanced seed oils. Using high-throughput camera-based phenotyping, the researchers will test the engineered crops under diverse environmental conditions and use that data to improve the new lines. Specialized biocontainment technology will ensure the plants’ genetic modifications do not escape into other crops or wild species.

Cahoon expects the team’s work to have impacts beyond pennycress and camelina. Findings related to the plastid’s metabolic circuitry, as well as the synthetic biology tools, will be valuable to scientists pursuing next-generation engineering of other plant oil feedstocks.

“The project really pushes the boundaries because we’re gaining fundamental knowledge while also developing advanced synthetic biology tools, and then bringing those two pieces together,” he said.

In addition to Nebraska and CU Boulder, the team includes investigators from Washington State University, Kansas State University, Montana State University, University of Minnesota, University of Missouri and the Donald Danforth Plant Science Center.

The grant was awarded under the DOE program Biosystems Design to Enable Safe Production of Next-generation Biofuels, Bioproducts and Biomaterials.