Photosynthetic hydrogen production by a hybrid complex of photosystem I and [NiFe]-hydrogenase.

Nature provides key components for generating fuels from renewable resources in the form of enzymatic nanomachines which catalyze crucial steps in biological energy conversion, for example, the photosynthetic apparatus, which transforms solar power into chemical energy, and hydrogenases, capable of generating molecular hydrogen. As sunlight is usually used to synthesize carbohydrates, direct generation of hydrogen from light represents an exception in nature. On the molecular level, the crucial step for conversion of solar energy into H(2) lies in the efficient electronic coupling of photosystem I and hydrogenase. Here we show the stepwise assembly of a hybrid complex consisting of photosystem I and hydrogenase on a solid gold surface. This device gave rise to light-induced H(2) evolution. Hydrogen production is possible at far higher potential and thus lower energy compared to those of previously described (bio)nanoelectronic devices that did not employ the photosynthesis apparatus. The successful demonstration of efficient solar-to-hydrogen conversion may serve as a blueprint for the establishment of this system in a living organism with the paramount advantage of self-replication.