THE HYDROGENASE FROM THE HYPERTHERMOPHILIC ARCHAEON PYROCOCCUS-FURIOSUS - FROM BASIC RESEARCH TO POSSIBLE FUTURE APPLICATIONS

The tetrameric hydrogenase from the hyperthermophilic archaeon Pyrococ cus furiosus has been genetically characterized and tested as catalyst in a light-mediated in vitro hydrogen production system under differe nt experimental conditions. The genetic analysis of the hydrogenase po ints out a possible bifunctional nature of the enzyme in which the bet a and gamma subunits might be responsible for elemental sulfur reducti on, whereas the delta and alpha subunits could be associated to the hy drogenase activity. Experiments on photoinduced hydrogen production pe rformed with the P. furiosus enzyme coupled to the semiconductor titan ium dioxide in the presence of methylviologen as an electron carrier s how that the system evolved H-2 with a rate as high as 0.5 mu moles/mi n/mg of TiO2. Interestingly, H-2 is produced even in the absence of MV . Since the experimental data reported here indicate that the inactiva tion of the electron carrier is the limiting point of the system, the P. furiosus hydrogenase can be considered a promising catalyst for thi s kind of in vitro system. Copyright (C) 1996 International Associatio n for Hydrogen Energy