In a $US1.4 million ($A1.8 million), three-year study, researchers are focusing on genetically altering lignin – a compound in cell walls that contributes to plants’ structural strength, but hinders extraction of cellulose – and testing the effect of these changes on the quality of plants used to produce biofuels.

The US Department of Energy aims to replace 30% of the country’s annual fossil fuel consumption with biofuels by 2030.

Biochemist and Purdue University researcher Clint Chapple said what was needed was a whole set of plants that were well-adapted to particular growing regions and had high levels of productivity for use in biofuels production.

The researchers are focusing specifically on the genetic modification of a hybrid poplar to reduce the hindrance of lignin on the plant’s ability to produce cellulose, which is in turn used to produce ethanol.

The alteration of lignin could mean the compound could be used not only in fuel, but in other products as well.

Currently the lignin, which makes up about 25% of plant material, can only be burned to provide energy for ethanol production, but cannot be converted into the biofuel.

The researchers said using the hybrid poplar and its relatives as the basis for biofuels had a number of advantages for the environment, farmers and the economy.

Researcher Richard Meilan said the poplar was a low-maintenance crop that was planted and harvested after seven years.

Corn, which is currently used in ethanol production, can only grow in a few areas around the world, whereas the poplar can grow across many climates making it more suitable for ethanol production.

“We need a bioenergy crop that can grow many places year-round,” Meilan said.

“The genus Populus includes about 30 species that grow across a wide climatic range from the subtropics in Florida to subalpine areas in Alaska, northern Canada and Europe.”

The researchers said using the hybrid poplar in its present form could produce about 70 gallons (265 litres) of fuel per tonne of wood.

About 10 tonnes of poplar could be grown per acre annually, producing 700 gallons of ethanol.

By changing the lignin composition annual production could increase to 1000 gallons of ethanol per acre.

According to the researchers, if the trees were planted on 110 million acres of unused farmland, this could replace 80% of the transportation fossil fuel consumed in the US each year.