The present energy crisis due to the use of petrol and the main fuel, led to the stimulation of research networks aiming at alternatives. The energy sources that are needed to be offered to the consumer should meet environmental issues, i.e. the development of clean fuels is required. The production of hydrogen by biological systems has been considered as a promising approach. Therefore the better knowledge of hydrogen metabolism, namely the function and structure of hydrogenases from different organisms is important. The use of hydrogenases from microorganisms has been under study in several laboratories in the EU, USA and Japan. Indeed, R&D programs currently supported by the governments dealing with the fundamental knowledge of hydrogen metabolism to its application has been carried out for years. The importance can be highlighted by the fact that the next 7th Framework Programme has a special program , the European Hydrogen and Fuel Cell Technology Platform. A recent trial of vehicles – buses – moved using the hydrogen-powered electric engines, which emit water vapor as a by-product was a clear indication of the key role of hydrogen. The use of hydrogen can cut greenhouse gas emissions substantially, however the main obstacle is the cost and trouble associated with producing a suitable supply of hydrogen. During the last few years COST has been playing a major role the research on hydrogen metabolism by sponsoring networks of laboratories working in different research lines within this common topic. The output of the Action 841 is clear from the novel results obtained, namely (a) the role of structural units in hydrogen activation by hydrogenases at molecular level (b) on the biodiversity of hydrogen producing systems, (c) on the genetic and physiological basis of hydrogenases function and (d) new technical development for the exploitation of hydrogen production. The results from the different aims could be achieved and integrated by bringing together skills in microbiology, biochemistry, molecular biology and biotechnology. This building of networks and the merging of different knowledge led to answer questions in a coherent form.
