The invention provides oxygen- resistant iron-hydrogenases
([Fe]-hydrogenases) for use in the production of H2. Methods used in the
design and engineering of the oxygen-resistant [Fe]-hydrogenases are
disclosed, as are the methods of transforming and culturing appropriate
host cells with the oxygen-resistant [Fe]-hydrogenases. Finally, the
invention provides methods for utilizing the transformed, oxygen
insensitive, host cells in the bulk production of H.sub.2 in a light
catalyzed reaction having water as the reactant.