NREL studies promising eucalyptus lines for biofuels

Eucalyptus has been found to be a promising option as a biomass feedstock for the production of liquid fuel, as researchers from the US Department of Energy's (DoE) National Renewable Energy Laboratory (NREL) have identified a tree that releases more than twice the usual amount of sugar.

The trees being studied by NREL are lignin-modified eucalyptus lines that have been developed for research by ArborGen of Summerville, South Carolina in the US.

'What makes this research particularly interesting is the increased ease with which the sugars are released,' highlights Angela Ziebell of NREL. 'The challenge is not just how much sugar a plant contains, but whether or not the plant will release that sugar without excessive processing. That is what makes it valuable as a liquid fuels source.

'We think the result of this technology may increase the potential of eucalyptus as a biomass source for liquid fuels. This result is particularly exciting given that efficient sugar release from plants is an obstacle to achieving affordable biofuels.'

'Through genetic modification, ArborGen has been able to alter the lignin content of a tree species, making the sugar much more accessible,' adds Maud Hinchee, chief science officer of ArborGen.

In order to overcome the issues associated with releasing sugars, including cost and environmental impact, ArborGen scientists have developed a low lignin eucalyptus: E. grandis x E. urophylla.

Using plant biotechnology, the modifications were made at two points in the lignin biosynthetic pathway, with the largest increase in sugar release coming from cinnamate-4-hydroxlase (C4H down-regulation). C4H lines have an estimated biomass productivity of 10 dry tonnes per acre per year, with the potential to produce about 1,000 gallons of biofuels per acre.