Researchers at Ruhr-Universität Bochum and the Freie Universität Berlin have clarified the crucial catalytic step in the production of hydrogen by enzymes. The enzymes, called [FeFe]-hydrogenases, efficiently turn electrons and protons into hydrogen. They are thus a candidate for the biotechnological production of the potential energy source. “In order to produce hydrogen on an industrial scale with the aid of enzymes, we must precisely understand how they work,” says Prof. Thomas Happe, one of the authors of the study.