Daniel G. Nocera
Daniel G. Nocera, Patterson Rockwood Professor of Energy at Harvard University, will present “Fuels to Food from Sunlight, Air and Water” at a Director’s Special Colloquium Thursday, Jan. 26, 2017, at 10:30 a.m. in the Bldg. 402 Auditorium. All employees whose schedules permit are invited to attend.
Abstract
Hybrid inorganic/biological 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, an oxygen evolving complex of Photosystem II was mimicked, the most important property of which was the self-healing nature of the catalyst. Self-healing permits water splitting to be accomplished under benign conditions. The ability to proceed with water splitting at neutral pH has the major benefit of 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 hybrid microbial/artificial leaf system scrubs 180 grams of CO2 from air, equivalent to 230,000 liters of air per 1 kWh of electricity. This hybrid device, called the bionic leaf, operates at unprecedented solar-to-biomass (10.7 percent) and solar-to-liquid fuels (6.2 percent) yields, greatly exceeding the 1 percent yield of natural photosynthesis. Extending our approach, we have discovered a renewable and distributed synthesis of ammonia at ambient conditions by coupling solar-based water splitting to a nitrogen fixing bioorganism in a single reactor. Nitrogen is fixed to ammonia by using the hydrogen produced from water splitting to power a nitrogenase installed in the bioorganism. The ammonia produced by the nitrogenase can be diverted from biomass formation to an extracellular product with the addition of an inhibitor. The nitrogen reduction reaction proceeds at a turnover number of 8 × 109 per cell and operates without the need for a carbon feedstock (which is provided by CO2 from air). This approach can be powered by distributed renewable electricity, enabling sustainable crop production (as will be shown in the talk).
Biography
Daniel G. Nocera is a chemist and leading researcher in renewable energy. His research group has pioneered studies of the basic mechanisms of energy conversion in biology and chemistry. He accomplished a solar fuels process of photosynthesis — the splitting of water to hydrogen and oxygen using sunlight and translated this science to produce the artificial leaf, which was named by Time magazine as Innovation of the Year for 2011. He has since elaborated this invention to create the bionic leaf, which performs artificial photosynthesis that is ten times more efficient than natural photosynthesis. This science discovery sets a course for the large-scale deployment of solar energy, especially to those of the emerging world. His research contributions in renewable energy have been recognized by several awards, some of which include the Leigh Ann Conn Prize for Renewable Energy, Eni Prize, IAPS Award, Burghausen Prize, Elizabeth Wood Award and the United Nation’s Science and Technology Award and from the American Chemical Society the Inorganic Chemistry, Harrison Howe. Kosolapoff and Remsen Awards. He is a member of the American Academy of Arts and Sciences, the U.S. National Academy of Sciences and the Indian Academy of Sciences. He is Editor-in-Chief of Chemical Science and is a frequent guest on TV and radio, and is regularly featured in print. He founded the energy company Sun Catalytix and its technology is now being commercialized by Lockheed Martin.