The current interest in biorefinery development is linked to the country’s access to a large amount of renewable carbon in the form of biomass. Recent work has identified a sustainable biomass supply in the United States of 1.3×109 tons/year without upsetting normal supplies of food, feed and fiber, and without requiring extensive changes in infrastructure or agricultural practices and the current surge of production of corn-based ethanol will drive production even higher. Second-generation facilities for ethanol production will rely on lignocellulose, and the renewable fuels standard has legislated cellulose as the source of 16 billion gallons of fuel ethanol by 2022.