PLATINIZED ALGAE: STABLE PHOTOCATALYTIC SYSTEMS FOR HYDROGEN PRODUCTION

HYDROGEN IS AN IDEAL FUTURE FUEL. IN AN ERA OF DECLINING CHEAP FOSSIL FUELS, WATER IS AN ALMOST INEXHAUSTIBLE SOURCE OF HYDROGEN AND OXYGEN. UTILIZATION OF SOLAR ENERGY IN THE BIOCATALYTIC APPROACH TO WATER SPLITTING IS ATTRACTIVE ECONOMICALLY, SINCE THE LIGHT-HARVESTING MECHANISM AND THE ACTIVE REDOX CENTERS FOR WATER SPLITTING EXIST IN HIGHER PLANTS AND ALGAE. HOWEVER, SYSTEMS FOR THE BIOPRODUCTION OF HYDROGEN ARE IMPRACTICAL, FOR AT LEAST ONE OF THE FOLLOWING REASONS: (A) THE PHOTOSYSTEMS OF ISOLATED PLANT (THYLAKOID) MEMBRANES BECOME INACTIVE AFTER A SHORT PERIOD; (B) HYDROGEN PRODUCTION IS OFTEN DEPENDENT UPON HIGHLY OXYGEN-SENSITIVE ENZYMES (E.G., HYDROGENASES), AND (C) SOME PHOTOBIOLOGICAL HYDROGEN-PRODUCING SYSTEMS DEPEND UPON ELECTRON TRANSFER RELAYS, SUCH AS METHYL VIOLOGEN, THAT ARE AUTO-OXIDIZABLE AND LIGHT-SENSITIVE. THE GOAL OF THE PROPOSED RESEARCH WORK IS TO UTILIZE A SINGLE TECHNIQUE TO OVERCOME THESE BASIC PROBLEMS THAT RESTRICT THE USE OF BIOLOGICAL SYSTEMS AS PHOTOCATALYTIC SYSTEMS FOR THE PRODUCTION OF HYDROGEN AND OXYGEN FROM WATER. IN THIS PROPOSAL, WE HAVE DESCRIBED THE PRINCIPAL FOR, AND THE BASICSTEPS REQUIRED TO, TEST THE FEASIBILITY OF DEPOSITING LOW AMOUNTS OF METALLIC PT DIRECTLY ONTO THE PHOTOSYNTHETIC MEMBRANES OF INTACT CELLS OF BLUE-GREEN ALGAE AS A MEANS OF ACHIEVING A LOW-COST PHOTOCATALYTIC MATERIAL WITH LONG-TERM STABILITY.