Eucalyptus Trees Could be Next Source for Biodiesel

John Davis

XBD201403-00482-20.TIFThey’re not just to stuff the faces of koala bears anymore – eucalyptus trees could serve as the next source for biodiesel and other biofuels. Work in part at the U.S. Department of Energy’s Joint Genome Institute is looking at genome sequencing to get the most out of the hardwood that won’t compete with food crops.

Combing through the 36,000-plus genes found in Eucalyptus (nearly twice as many as in the human genome), the researchers homed in on those that may influence the production of secondary cell wall material that can be processed for pulp, paper, biomaterials and bioenergy applications. Approximately 80 percent of the woody biomass in a Eucalyptus is made of cellulose and hemicellulose, both long chains of sugars, with the remaining biomass primarily comprised of lignin, the tough “glue” that holds it all together.

“A major challenge for achieving a sustainable energy future is our understanding of the molecular basis of superior growth and adaptation in woody plants suitable for biomass production,” said [Alexander Myburg of the University of Pretoria in South Africa].

“We have a keen interest in how wood is formed,” said [Gerald Tuskan of the Oak Ridge National Laboratory and the BioEnergy Science Center and U.S. Department of Energy Joint Genome Institute (DOE JGI)]. “A major determinant of industrial processing efficiency lies in the composition and cross-linking of biopolymers in the thick secondary cell walls of woody fibers. Our analysis provides a much more comprehensive understanding of the genetic control of carbon allocation towards cell wall biopolymers in woody plants—a crucial step toward the development of future biomass crops.”

An additional finding by the team was that among sequenced plants to date, Eucalyptus showed the highest diversity of genes for specialized metabolites such as terpenes. These hydrocarbons serve as chemical self-defenses against pests, as well as providing the familiar aromatic essential oils used in both medicinal cough drops and for industrial processes.

The researchers believe that eventually eucalyptus could serve as a feedstock for biofuels for jets.

Biodiesel, biomass