121st General Meeting of the KCS

Type Plenary Lecture
Area Plenary Lecture
Room No. Halla Hall A
Time THU 13:30-:
Code PLEN-1
Subject Fuels to Food from Sunlight, Air and Water
Authors Daniel G. Nocera
Patterson Rockwood Professor of Energy, Department of Chemistry and Chemical Biology, Harvard University, United States
Abstract Hybrid biological | inorganic (HBI) constructs have been created to use sunlight, air and water to accomplish carbon fixation and nitrogen fixation, thus enabling distributed and renewable fuels and crop production. The carbon fixation cycle begins with the artificial leaf, which was invented to accomplish the solar fuels process of natural photosynthesis – the splitting of water to hydrogen and oxygen using sunlight – under ambient conditions. To create the artificial leaf, self-healing oxidic catalysts were integrated with silicon by developing novel patterning techniques. The property of self-healing catalysis allows water splitting to be accomplished under benign conditions and at neutral pH thus allowing water splitting catalysis to be interfaced with bioorganisms. Using the tools of synthetic biology, a bio-engineered bacterium has been developed to convert carbon dioxide, along with the hydrogen produced from the catalysts of the artificial leaf, into biomass and liquid fuels, thus closing an entire artificial photosynthetic cycle. This HBI system, called the bionic leaf, operates at unprecedented solar-to-biomass (10.7%) and solar-to-liquid fuels (6.2%) yields, greatly exceeding the 1% yield of natural photosynthesis. Extending this approach, a renewable and distributed synthesis of fertilizer and ammonia have been achieved at ambient conditions by coupling solar-based water splitting to a nitrogen fixing bioorganism. The nitrogen reduction reaction proceeds at a turnover number of 3.1 × 109 per cell and operates without the need for a carbon feedstock (which is provided by CO2 from air). These science discoveries set the stage for a storage mechanism for the large scale, distributed, deployment of solar energy and distributed food production and thus are particularly useful to the poor of the world, where large infrastructures for fuel and food production are not tenable.
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