Corn substitutes remain too expensive.

• Position: Ethanol Production

The production of ethanol from lignocellulose-rich materials such as wood residues, waste paper, used cardboard, and straw cannot yet be achieved at the same efficiency and cost as from corn starch.

A cost comparison has concluded that using lignocellulose materials is unlikely to be competitive with starch until 2020 at the earliest. The study, published in Biofuels, Bioproducts & Biorefining, did identify many opportunities for reducing costs and improving income within the lignocellulose-to-ethanol process, and provides insight into the priority areas that must be addressed in coming years.

Ethanol can be blended with gasoline to reduce our dependency on fossil fuels. The last 15 years have seen a massive growth of so-called first-generation processes that use enzymes and bacteria to turn the starch and sugars in corn and sugarcane into ethanol, but com and sugarcane also are important components of the human food web, so using them for ethanol production has the potential to affect the price and availability of these basic commodities.

On the other hand, lignocellulose materials often are hard to dispose of, but they are rich in sugars that can be fermented into ethanol following appropriate processing. "Not only is cellulose the most abundant polymer on Earth, it cannot be digested by humans, so using it for fuel production does not compete directly with food supplies," says the study's lead author Jamie Stephen, who works in the Department of Wood ,Science at the University of British Columbia, Vancouver, Canada. "The race is on to commercialize this second...