Engineering duckweed to produce oil for biofuels, bioproducts

Scientists at the U.S. Department of Energy's Brookhaven National Laboratory and collaborators at Cold Spring Harbor Laboratory (CSHL) have engineered duckweed to produce high yields of oil.

The team added genes to one of nature's fastest growing aquatic plants to "push" the synthesis of fatty acids, "pull" those fatty acids into oils, and "protect" the oil from degradation. As the scientists explain in a paper published in Plant Biotechnology Journal, such oil-rich duckweed could be easily harvested to produce biofuels or other bioproducts.

The paper describes how the scientists engineered a strain of duckweed, Lemna japonica, to accumulate oil at close to 10% of its dry weight biomass. That's a dramatic, 100-fold increase over such plants growing in the wild – with yields more than seven times higher than soybeans, today's largest source of biodiesel.

"Duckweed grows fast," said Brookhaven Lab biochemist John Shanklin, who led the team. "It has only tiny stems and roots – so most of its biomass is in leaf-like fronds that grow on the surface of ponds worldwide. Our engineering creates high oil content in all that biomass.

"Growing and harvesting this engineered duckweed in batches and extracting its oil could be an efficient pathway to renewable and sustainable oil production," he said.

Two added benefits: As an aquatic plant, oil-producing duckweed wouldn't compete with food crops for prime agricultural land. It can even grow on runoff from pig and poultry farms.

Image source: Brookhaven National Laboratory.