Cellulose Success; April 2008; Scientific American Magazine; by Steven Ashley; 2 Page(s)
Not too long ago many investors made the bet that renewable fuels from biomass would be the next big thing in energy. Converting corn, sugarcane and soybeans into ethanol or diesel-type fuels lessens our nation's dependence on oil imports while cutting carbon dioxide emissions. But already the nascent industry faces challenges. Escalating demand is hiking food prices while farmers clear rain-forest habitats to grow fuel crops. And several recent studies say that certain biofuel-production processes either fail to yield net energy gains or release more carbon dioxide than they use.
A successor tier of start-up ventures aims to avoid those problems. Rather than focusing on the starches, sugars and fats of food crops, many of the prototype bioethanol processes work with lignocellulose, the "woody" tissue that strengthens the cell walls of plants, says University of Massachusetts Amherst chemical engineer George W. Huber. Although the cellulose breaks down less easily than sugars and starches and thus requires a complex series of enzyme-driven chemical reactions, its use opens the industry to nonfood plant feedstocks such as agricultural wastes, wood chips and switchgrass. But no company has yet demonstrated a cost-competitive industrial process for making cellulosic biofuels.