Photosynthesis as a power supply for (bio-)hydrogen production.

Although hydrogen is considered to be one of the most promising future energy sources and the technical aspects involved in using it have advanced considerably, the future supply of hydrogen from renewable sources is still unsolved. This review focuses on the production of hydrogen from water using biological catalysts that have been optimized by nature: the process of water-splitting photosynthesis on the one hand and hydrogen production via the catalyst hydrogenase on the other. Using water as a source of electrons and sunlight as a source of energy, both engineered natural systems and biomimetic (bio-inspired) model systems can be designed as first steps towards water-splitting-based hydrogen production (biophotolytic hydrogen production).

Light-driven water splitting for (bio-)hydrogen production: photosystem 2 as the central part of a bioelectrochemical device.

To establish a semiartificial device for (bio-)hydrogen production utilizing photosynthetic water oxidation, we report on the immobilization of a Photosystem 2 on electrode surfaces. For this purpose, an isolated Photosystem 2 with a genetically introduced His tag from the cyanobacterium Thermosynechococcus elongatus was attached onto gold electrodes modified with thiolates bearing terminal Ni(II)-nitrilotriacetic acid groups. Surface enhanced infrared absorption spectroscopy showed the binding kinetics of Photosystem 2, whereas surface plasmon resonance measurements allowed the amount of protein adsorbed to be quantified.