Grass to Gas: A Novel Strategy for Cellulosic Ethanol Production

The only sustainable source of liquid transportation fuel that may replace the world's finite supply of oil is solar energy captured by plants and stored as "biomass." Advanced biofuels are derived from non-food biomass (e.g., agricultural residues, biomass crops, municipal wastes) and promise significant societal and environmental benefits: improved rural economies, decreased dependence on imported oil, and reduced greenhouse gas emissions. One example of a potentially beneficial advanced biofuel is cellulosic ethanol. The benefits of cellulosic ethanol result, at least in part, because all non-food parts of plants are utilized. However, the recalcitrance of plants to bioprocessing and the scarcity of effective microbes capable of fermenting the wide range of biomass components pose significant impediments to the development of commercially viable processes for cellulosic ethanol production. Current processes are complex and only marginally cost-effective. An approach we have used to overcome hurdles to viable sustainable biofuels production involves tapping the natural diversity that exists in soil microbial communities. At the UMass Amherst, we developed a microbial biomass processing technology that employs a novel bacterium from forest soil known as the Q Microbe, which converts all major components of biomass into ethanol. Properties of the Q Microbe indicate that it is an ideal organism for use in a biomass conversion scheme in which production of enzymes, biomass decomposition, and fermentation to ethanol are all consolidated in a single step, yielding significant economic and environmental advantages.