Improved synthesis of hydrogen gas in genetically modified organisms by expression of oxidoreductases and ferredoxin, and improved hydrogenase activity and hydrogen synthesis in genetically modified organisms in the presence of oxygen with enhanced expression of e. coli isc-operon

The present invention relates to a modified recombinant host cell, wherein the cell is modified to contain at least one heterogeneous gene, wherein the heterogeneous gene is selected from the genes coding for a ferredoxin-dependent hydrogenase and oxidoreductase and ISC-operon. The present invention also relates to a method for producing hydrogen, wherein the method comprises the steps of: preparing such a modified recombinant host cell culturing the host cell in a medium; and collecting hydrogen. The present invention also relates to a modified host cell which has an enhanced hydrogenase activity by deletion of the iscR-gene.