High Rate and Yield Hydrogen Fermentations

76205-Before hydrogen fuel can be economically produced by the bacterial fermentation of sugars and carbohydrates, increases in both the rate and yield of the process are required. Current processes exhibit modest rates and yields, which are only about one fourth that of competitive ethanol fuel fermentations. The target cost requirement is $1.50/kg hydrogen. This project will demonstrate that high yield and rate hydrogen fermentations are feasible, and will develop technology to make hydrogen fuels competitive with ethanol production from corn starch. The high hydrogen yields will be achieved by metabolic (genetic) engineering of bacterial strains, diverting their energy metabolism from growth to hydrogen production. Phase I will demonstrate feasibility by using a model bacterial system in which hydrogen evolution from sugars is coupled to energy yielding respiratory reactions, thereby providing an increased hydrogen yield. Hydrogen fermentations will also be studied in continuous cultures to determine their maximal rates. Commercial Applications and Other Benefits as described by the awardee: The production of hydrogen by fermentation processes could become a future, lower-cost alternative to vehicular fuel ethanol production from corn starch. The hydrogen produced from these fermentations would be a renewable fuel source that does not generate greenhouse gases.