Renewable hydrogen fuel has for many years put forth as the ultimate clean energy carrier. If produced from solar or wind power it would diminish the world's dependence on coal, oil and gas, thus tackling the challenge of global warming. Still, the question remains on how to produce hydrogen on large-scale with methods that are both environmentally friendly and economically viable. Traditional electrochemical production is generally expensive and rely on scarce and expensive noble metals. Despite these drawbacks, facilities employing such technologies are currently being successfully employed in e.g. Norway and Germany, underscoring that this technology is on the rise. However, in order to enable a global-scale future hydrogen society new methods for hydrogen gas production needs to be developed. Remarkably, evolution has already developed an efficient hydrogen economy, in which the production and utilization of hydrogen gas is handled by enzymes called hydrogenases. These biological catalysts operate with efficiencies on par with current state-of-the-art manmade systems without any dependence on precious or rare metals. Consequently, hydrogenases can be employed either for the production of hydrogen gas as a biofuel using genetically modified microorganisms, or alternatively, the isolated enzyme can be incorporated into devices similar to current platinum based technologies. Still, a number of challenges remain before these biological catalysts can be implemented in a technological context, as we still do not fully understand how they function or how we can optimize them for our needs. In this project we are addressing these questions using a combination of biology and chemistry techniques. In short, the project is expected to provide unprecedented insight into both the assembly and function of these remarkable enzymes. Moreover, our unusual interdisciplinary approach allows us to develop new methods for working with, and manipulating, not only hydrogenases but also other metalloenzymes.