Biophotolytic H₂ production using alginate-immobilized chloroplasts, enzymes and synthetic catalysts

Abstract

Hydrogen can be produced by illumination of an aqueous mixture of chloroplasts and hydrogenase, in the presence of an electron carrier^1,2. This system may have potential for development of a solar converter to produce hydrogen from water^3,4 if it can be stabilized or constructed as a completely synthetic system. The immobilization of the chloroplasts, or membrane analogues, would make possible a one-stage reactor with all the components in one chamber, or a two-stage reactor if the electron carrier was passed to another chamber to react with an immobilized hydrogen-producing catalyst. However, techniques for immobilizing enzymes tend to yield immobilized chloroplasts that are not very active, and other methods must be used^5–8 . We describe here the immobilization of chloroplasts using calcium alginate gels on reinforcing grids of nylon and stainless steel. Chloroplasts thus immobilized are fully active and can be used to produce hydrogen gas. Strengthened films of this sort could provide a good, solid, rigid matrix for a solar converter.