ABSTRACT
Biofuels have the potential to contribute signicantly in meeting the challenges of the global energy crisis as they replace fossil fuels and provide a number of environmental and economic benets. The most widely used biofuel for transportation worldwide so far is bioethanol produced from corn grain, sugarcane, and biomass. Reducing dependence on fossil fuel is a key element of the energy policy adapted by many nations (Srinivasarao et al. 2013). At present, global production of ethanol exceeds 85 billion liters per year using sugarcane (60%), maize grain, sorghum grain, wheat grain, and sugar beet (40%) as feedstocks. The U.S. Energy Independence and Security Act RFS2 (EISA 2007) has set an ambitious target to triple the current 12 billion gallons a year biofuel use by 2022, with 21 billion gallons coming from advanced biofuels. In 2011, the United States used 40% of its corn production for ethanol, generating serious concerns about the future of food versus fuel. Generating biofuels from food crops is unsustainable because the high demand for biofuels will create a shortage in supplies because more and more of these crops will be diverted from food supply to biofuel production. Although crops such as corn and sugarcane are expected to remain important sources of biofuels, greater emphasis is being placed on other potential energy crops such as grasses and nonfood crops.
