Biofuels is a type of fuel whose energy is derived from biological carbon fixation. Biofuels include fuels derived from biomass conversion, as well as solid biomass,liquid fuels and various biogases. Although fossil fuels have their origin in ancient carmon fixation, they are not considered biofuels by the generally accepted definition because they contain carbon that has been "out" of the carbon cycle for a very long time. Biofuels are gaining increased public and scientific attention, driven by factors such as oil plice hikes, the need for increased enagy security, concern over greenhouse gass emissions from fossil fuels, and support from government subsiders.
BIoethanol is an alchol made by fermentation, mostly from carmonhydrates produced in sugur or starch crops such as corn or sugarcane. Cellulosic Biomass, derived from non-food sources such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline abbtive to increase octane and improve vehicle emissions. Bioethanol is widely used in the UsSAand in Brazil. Current plant design does not provide for converting the lignin portion of plant raw materials to fuel components by fermentation.