Today, carbon-rich fossil fuels, primarily oil, coal, and natural gas, provide 85% of the energy consumed in the US As world demand increases, oil reserves may become rapidly depleted (1). Fossil fuel use increases CO2 emissions and raises the risk of global warming. The high energy content of liquid hydrocarbon fuels makes them the preferred energy source for all modes of transportation. In the US alone, transportation consumes› 13.8 million barrels of oil per day and generates" 0.5 gigatons of carbon per year (2). This release of greenhouse gases has spurred research into alternative, nonfossil energy sources. Among the options (nuclear, concentrated solar thermal, geothermal, hydroelectric, wind, solar, and biomass), only biomass has the potential to provide a high-energy-content transportation fuel. Biomass is a renewable resource that can be converted into carbon-neutral transporation fuels. Currently, biofuels such as ethanol are produced largely from grains, but there is a large, untapped resource (estimated at more than a billion tons per year) of plant biomass that could be utilized as a renewable, domestic source of liquid fuels. Well-established processes convert the starch content of the grain into sugars that can be fermented to ethanol. The energy efficiency of starch-based biofuels is however not optimal, while plant cell walls (lignocellulose) represent a huge untapped source of energy (3). Plantderived biomass contains cellulose, which is more difficult to convert to sugars; hemicellulose, which contains a diversity of carbohydrates that have to be efficiently degraded by microorganisms to fuels; and lignin, which is recalcitrant to degradation and prevents cost-effective fermentation. The development of cost-effective and energy-efficient processes to transform lignocellulosic biomass into fuels is hampered by significant roadblocks, including the lack of specifically developed energy crops, the difficulty in separating biomass components, low activity of enzymes used to deconstruct biomass, and the inhibitory effect of fuels and processing byproducts on organisms responsible for producing fuels from biomass monomers. The Joint BioEnergy Institute (JBEI) is a US Department of Energy (DOE) Bioenergy Research Center that will address these roadblocks in biofuels production. JBEI draws on the expertise and capabilities of three national laboratories (Lawrence Berkeley National Laboratory (LBNL), Sandia National Laboratories (SNL), and Lawrence Livermore National Laboratory (LLNL)), two leading US universities (University of California campuses at Berkeley (UCB) and Davis (UCD)), and a foundation (Carnegie Institute for Science, Stanford) to develop the scientific and technological base needed to convert the energy stored in lignocellulose into transportation fuels and commodity chemicals. Established scientists from the participating organizations are leading teams of researchers to solve the key scientific problems and develop the tools and infrastructure that will enable other researchers and companies to rapidly develop new biofuels and scale production to meet US transportation needs and to develop and rapidly transition new technologies to the commercial sector.

JBEI’s biomass-to-biofuels research approach is based in three interrelated scientific divisions and a technologies division. The Feedstocks Division will develop improved plant energy crops to serve as the raw materials for biofuels. The Deconstruction Division will investigate the conversion of this lignocellulosic plant material to sugar and aromatics. The Fuels Synthesis Division will create microbes that can efficiently convert sugar and aromatics into ethanol and�…