Amongst the arguments against growing crops for use as biofuel feedstock is the fact that they displace food crops. However, what if they could be grown on marginal land that wouldn't be suitable for food crops anyway? Well, that's the case with sugarcane. Now, genetically-engineered types of sugarcane may make it a more valuable source of biofuel than ever before.

Led by the University of Illinois, a multi-institution team created varieties of sugarcane that have much more oil in their leaves and stem than unmodified varieties. That oil could be used in biodiesel production. It was assumed that this boost in oil production would result in less sugar production, although that turned out not to be the case. That's a good thing, as that sugar can be used to produce ethanol.

The scientists ran the sugarcane through a juicer, simultaneously extracting about 90 percent of the sugar and 60 percent of the oil. Using a patented technique, that mixture was subsequently fermented to produce ethanol, then treated with organic solvents to recover the oil.

So far, the team has created sugarcane plants that are 13 percent oil, 8 percent of which is the type that could be made into biodiesel. Even if that figure were just 5 percent, the researchers claim that it would amount to "an extra 123 gallons [466 l] of biodiesel per acre than soybeans and 350 more gallons [1,325 l] of ethanol per acre than corn."

That said, the project is currently hoping to boost that oil content figure to 20 percent, which is the theoretical maximum limit.

A paper on the research was recently published in the journal Biocatalysis and Agricultural Biotechnology.