The water oxidation enzyme in the photosystem is largely responsible for converting solar energy into the high-energy chemical compounds needed to sustain life on the planet, and which have accumulated in the form of fossil fuels. This enzyme also produces the oxygen in the atmosphere that makes the biosphere aerobic, with all the associated repercussions (aerobic respiration, multicellular life, ozone protection, etc.). It is also the only catalyst capable of oxidizing water to its optimum thermodynamic potential. As a result, it is the focus of much attention, with the aim of better understanding how it works and producing bio-inspired catalysts potentially useful for the development of efficient energy conversion devices : a) production ofH2 by electrolysis or photolysis; b) production of electricity by fuel cells.
The Saclay group applies biophysical, biochemical and biological approaches to study the photochemistry and enzymology of this remarkable enzyme. These approaches are applied to enzymes isolated from thermophilic species of cyanobacteria, as they are more robust and homogeneous. The study focuses in particular on the metal ion cluster (4 Mn ions and one calcium ion). In parallel, we are synthesizing and studying chemical models that reproduce certain properties of the enzyme. These artificial systems could have applications in solar fuel production and fuel cells (supported by EU network Solar H2).
