Engineered Biomolecular Catalysts for Artificial Photosynthesis
Kara Bren, University of Rochester
Solar energy is clean, renewable, and abundant, but constitutes a minor energy resource worldwide. One reason why solar energy does not meet its potential is its intermittent and diffuse nature. Developing new approaches to storing solar energy thus is critical to fully utilizing this sustainable energy resource. One approach is to mimic photosynthesis, in which light energy is collected and converted to a storable form, specifically high-energy molecules such as sugars. An attractive target product for artificial photosynthesis is hydrogen. When hydrogen is produced from water in a light-driven reaction, it is a carbon-free, clean-burning fuel. In our work, we are aiming to develop biomolecular systems capable of producing hydrogen from water. A key component of such a system is a catalyst that facilitates hydrogen synthesis in an aqueous environment. We have chosen biomolecular catalysts for this work to take advantage of their favorable properties. One is that they function in water, unlike many synthetic and materials-based catalysts. Furthermore, using biomolecules facilitates the mimicking of features that natural systems use to achieve high efficiency such as pathways for protons and electrons, essential components of the reaction. In this talk, four different engineered biomolecular catalysts capable of yielding hydrogen from water will be presented. They range in complexity from small peptide-metal complexes to more intricate engineered respiratory proteins. These catalysts are shown to function in light energy storage by pairing them with nanoscale light-harvesting systems. The resulting nano-bio artificial photosynthetic systems yield hydrogen from water in a reaction driven only by visible light.