In 1925, Henry Ford observed that fuel is present in all vegetative matter that can be fermented and predicted that Americans would some day grow their own fuel. Last year, global biofuel production reached 28 billion US gallons, and biofuel accounted for 2.7% of the world's transportation fuel. Bioethanol, a popular type of biofuel, is largely derived from sugary food crops such as corn and sugarcane. However, technologies are being developed to generate bioethanol from non-food sources, such as the lignocellulosics present in switchgrass and trees. The sugars locked in the polymers of cell walls, i.e., cellulose, hemicellulose and lignin, can be extracted and fermented by yeast into bioethanol.
↧