The present application relates to the use of metabolically-engineered microbial cells for the production of hydrogen and hydrogenase enzymes. The microbial cells are strains of E. coli which are genetically engineered to optimize the cell for production of hydrogen or active hydrogenase. The strains of E. coli are transformed with at least one expression vector directed towards the biosynthesis of a hydrogenase enzyme. Methods of hydrogen production, fuel-cell systems and recombinant fuel-cell catalysts are also provided.
STATEMENT REGARDING FEDERALLY SPONSORED R&D
 Certain aspects of the invention disclosed herein were made with United States government support under the U.S. Department of Energy Grant No. DE-FG02-06ER15770. The United States government has certain rights in these aspects of the invention.