. Harvard Medical School, Harvard University’s Faculty of Arts and Sciences and Wyss Institute for Biologically Inspired Engineering called the system “a biological leaf”. The findings were published in the February 9th issue of Proceedings of the National Academy of Sciences. Humans are only beginning to understand how to harness sunlight. However, plants have been able to do this for over a billion years. They use solar energy (sunlight), to produce food from water and air. This is what we call photosynthesis. Image credit: Jessica Polka. Harvard Medical School. Researchers have discovered how to harness sunlight to produce hydrogen that can later be used to fuel your cells. Hydrogen has yet to be used as an engine for power generation or automobiles, since the world revolves around liquid fuels. Researchers have integrated the “artificial leaves” in their latest research. This “artificial Leaf” uses a catalyst that makes sunlight turn water into hydrogen and oxygen. It is also able to produce CO2 + hydrogen from a genetically engineered bacterium. The simplest secondary alcohol is Isopropanol, also known as C3H8O, C3H7OH and CH3CHOHCH3. Pamela Silver (Professor of Biochemistry and System Biology) called the system “bionic leaves”, in reference to Professor Daniel Nocera’s artificial leaf. Prof. Silver is part of the Wyss’ founding faculty. He said that the Wyss was a proof-of-concept system for harvesting and storing solar energy in liquid fuel. Dan’s remarkable discovery of the catalyst was the key to this. We set out on a mission to interconnect different types of organisms in the pursuit of harvesting solar energy. It was a great match!” The spark of an interest in “personalized energies” led to Professors Nocera & Silver collaborating shortly after Nocera’s move from MIT and Harvard. Both were interested in the concept of “personalized energy” (i.e. They were both interested in “personalized energy,” i.e., making energy local, as opposed to current systems, such as oil production that relies on centralization and fuel delivery at filling stations. They believed that local energy would prove attractive in emerging countries. Professor Silver stated that it’s not as if they’re trying make a complicated system. We are instead looking for simplicity, ease of use. Prof. Nocera uses catalysts that can be found in inexpensive and easily accessible materials to make his artificial leaf. Professor Nocera stated that the catalysts he made were extremely adaptable and compatible with growth conditions needed for living organisms such as bacteria. The artificial leaves produce hydrogen and oxygen and then the hydrogen is given to Ralstonia Eutropha, a bacterium. The enzyme converts the hydrogen to protons and electrons, and then adds CO2 to make more cells. Based on the previous findings of Anthony Sinskey at MIT, we discovered that new metabolic pathways within the bacterium can be engineered to make isopropanol. Brendan Colon is a Silver Lab graduate student in systems Biology. He said that interfacing an inorganic catalytic with biology gives you a unique platform for chemical synthesizing. This paper is about solar-to-chemical production. We have used plants to do this, but Prof. Silver suggested that the same principle could be applied to small amounts of vitamins. To improve efficiency, the scientists now have to optimize the enzyme and bacteria to make the bionic leaves more efficient at converting sunlight to biomass. The scientists are striving for a 5% efficiency in comparison to the 1% nature requires for photosynthesis, which converts solar energy into biofuel. Professor Nocera stated that they are almost at 1 percent conversion efficiency of sunlight to isopropanol. It has been nearly 2.6 billion years since the beginning of human evolution. Pam and I have worked together for a year, but we have not yet achieved photosynthesis efficiency. The research was jointly funded by the National Science Foundation, the Office of Naval Research and the Air Force Office of Scientific Research. Citation: “Efficient solar-to-fuels production from a hybrid microbial-water-splitting catalyst system,” Joseph P. Torella, Christopher J. Gagliardi, Janice S. Chen, D. Kwabena Bediako, Brendan Colon, Jeffery C. Way, Pamela A. Silver and Daniel G. Nocera. PNAS. February 9, 2015. DOI: 10.1073/pnas. 1424872112.
