(619f) Ethanol Production from the Fermentation of Synthesis-Gas

Ethanol is an economical and renewable energy source that is currently being used for fuel in a blended mix with gasoline. Currently, most ethanol is derived by fermenting corn. As ethanol demands increase, the current US corn base will be insufficient to meet both energy and food demands. Thus, alternate sources for producing ethanol is important as the world moves toward a renewable energy system. One alternative is to generate synthesis-gas by burning biomaterials such as switchgrass, trees, and waste wood products, then fermenting this synthesis-gas to ethanol. Certain microbes have been found that are capable of converting the components of synthesis-gas, such as carbon monoxide, hydrogen and carbon dioxide, into ethanol under anaerobic conditions. In this project, we evaluated the effectiveness of Clostridium carboxidivorans strain P7T in converting synthesis-gas into ethanol. This synthesis-gas was created by gasifying biomass and the composition of the synthesis-gas was dependent on the type of biomass used. The different compositions of the synthesis-gas have an effect on the amounts of ethanol that the microorganisms produced. The objective is to develop a process to produce the greatest amount of ethanol possible in a continuous production fermenter.