Genetic Characterization of a Single Bifunctional Enzyme for Fumarate Reduction and Succinate Oxidation in Geobacter sulfurreducens and Engineering of Fumarate Reduction in Geobacter metallireducens

↵¶ Present address: Centro de Astrobiología, Instituto Nacional de Técnica Aerospacial, Madrid, Spain.; † Present address: : Departamento de Microbiologia Molecular, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Cuernavaca, Morelos, Mexico.; § Present address: : Department of Geology and Geophysics, University of Wisconsin, Madison, Wis.; ‡ Present address: : Department of Microbiology, Biotechnology Institute, University of Minnesota, St. Paul, Minn.