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Home > Press > How to train your bacterium: Berkeley Lab scientists teach bacterium a new trick for artificial photosynthesis Abstract: Trainers of dogs, horses, and other animal performers take note: a bacterium named Moorella thermoacetica has been induced to perform only a single trick, but it's a doozy. Berkeley Lab researchers are using M. thermoacetica to perform photosynthesis - despite being non-photosynthetic - and also to synthesize semiconductor nanoparticles in a hybrid artificial photosynthesis system for converting sunlight into valuable chemical products. "We've demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with cadmium sulfide nanoparticles to produce acetic acid from carbon dioxide at efficiencies and yield that are comparable to or may even exceed the capabilities of natural photosynthesis," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this work. "The bacteria/inorganic-semiconductor hybrid artificial photosynthesis system we've created is self-replicating through the bio-precipitation of cadmium sulfide nanoparticles, which serve as the light harvester to sustain cellular metabolism," Yang says. "Demonstrating this cyborgian ability to self-augment the functionality of biological systems through inorganic chemistry opens up the integration of biotic and abiotic components for the next generation of advanced solar-to-chemical conversion technologies." Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley, is the corresponding author of a paper describing this research in Science. The paper is titled "Self-photosensitization of non-photosynthetic bacteria for solar-to-chemical production." Co-authors are Kelsey Sakimoto and Andrew Barnabas Wong. Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water. Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics. Yang and his research group have been at the forefront of developing artificial photosynthetic technologies that can realize the full potential of solar-to-chemical synthesis. "In our latest study, we combined the highly efficient light harvesting of an inorganic semiconductor with the high specificity, low cost, and self-replication and self-repair of a biocatalyst," Yang says. "By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, we enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction." Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an "electrograph" (meaning it can undergo direct electron transfers from an electrode), and an "acetogen" (meaning it can direct nearly 90-percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid artificial photosynthesis system. "Our hybrid system combines the best of both worlds: the light-harvesting capabilities of semiconductors with the catalytic power of biology," Yang says. "In this study, we've demonstrated not only that biomaterials can be of sufficient quality to carry out useful photochemistry, but that in some ways they may be even more advantageous in biological applications." ### This work was funded by the U.S. Department of Energy (DOE)'s Office of Science. The interface design part of the study was carried out the Molecular Foundry, a DOE Office Science User Facility hosted by Berkeley Lab. About Berkeley Lab Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit www.lbl.gov. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit the Office of Science website at science.energy.gov/. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Home > Press > A new way to look at MOFs: International study challenges prevailing view on how metal organic frameworks store gases Abstract: An international collaboration of scientists led by Omar Yaghi, a renowned chemist with the Lawrence Berkeley National Laboratory (Berkeley Lab), has developed a technique they dubbed "gas adsorption crystallography" that provides a new way to study the process by which metal-organic frameworks (MOFs) - 3D crystals with extraordinarily large internal surface areas - are able to store immense volumes of gases such a carbon dioxide, hydrogen and methane. This new look at MOFs led to a discovery that holds promise for the improved design of MOFs tailored specifically for carbon capture, or for the use of hydrogen and natural gas (methane) fuels. "Up to this point we have been shooting in the dark in our designing of MOFs without really understanding the fundamental reasons for why one MOF is better than another," says Yaghi. "Our new study expands our view and thinking about MOFs by introducing gas-gas interactions and their organization into superlattices that are a major factor in achieving high storage capacity for gases." Yaghi, who invented MOFs in the early 1990s while at the Arizona State University, is now a faculty scientist with Berkeley Lab's Materials Sciences Division and the University of California (UC) Berkeley Chemistry Department, where he also serves as co-director of the Kavli Energy NanoScience Institute (Kavli-ENSI). For this latest study, Yaghi and Osamu Terasaki, a chemist with Stockholm University, along with collaborators from institutes in the United States, China, South Korea and Saudi Arabia, interfaced a gas adsorption apparatus with a form of X-ray crystallography, called in-situ small angle X-ray scattering (SAXS). The result was a gas adsorption crystallography technique that uncovered evidence of cooperative interactions between gas molecules within a MOF. "These cooperative gas-gas interactions lead to highly organized behavior, which results in the formation of gas aggregates about 40 nanometers in size," Yaghi says. "The aggregates are arranged in orderly superlattice structures, which is in stark contrast to the prevailing view that the adsorption of gas molecules by MOFs occurs stochastically." Yaghi and Terasaki are the corresponding authors of a paper describing this study that has been published in Nature. The paper is titled "Extra adsorption and adsorbate superlattice formation in metal-organic frameworks." The lead authors are Hae Sung Cho, Hexiang Deng and Keiichi Miyasaka. Other co-authors are Zhiyue Dong, Minhyung Cho, Alexander Neimark and Jeung Ku Kang. Since Yaghi's original invention, thousands of different types of MOFs have been created. A typical MOF consists of a metal oxide center surrounded by organic molecules that form a highly porous three-dimensional crystal framework. The variations on this basic structure are virtually limitless and can be customized so that a MOF's pores adsorb specific gas molecules, making MOFs potentially ideal gas storage vessels. "One gram of MOF has a surface area of up to 10,000 square meters onto which it is possible to compact gas molecules into MOF pores like so many bees on a honeycomb without the high pressures and low temperatures usually required for compressed gas storage," Yaghi says. The selectivity and uptake capacity of a MOF are determined by the nature of the gas molecule being adsorbed and its interactions with the MOF's constituents. While the interactions of gas molecules with the internal surface of a MOF and among themselves within individual pores have been extensively studied, the gas-gas interactions across a MOF's pore walls have not been explored until now. With their SAXS-based gas adsorption crystallography technique, Yaghi, Terasaki and their collaborators discovered that local strain in the MOF induced by pore-filling can give rise to collective and long-range gas-gas interactions, resulting in the formation of superlattices that extend over several pores. "We were able to track and map the distribution and ordering of adsorbate molecules in five members of the mesoporous MOF-74 series along entire adsorption-desorption isotherms," Yaghi says. "In all cases, we found that the capillary condensation that fills the pores gives rise to the formation of extra-adsorption domains that span several neighboring pores and have a higher adsorbate density than non-domain pores." The next step, Yaghi says, will be to apply this new gas adsorption crystallography technique to other porous molecular systems that can serve as gas storage vessels, such as covalent organic frameworks (COFs) and zeolitic imidazolate frameworks (ZIFs). "We want to generate a comprehensive view of how various gases interact collectively within porous materials interior," says Yaghi. "We will then feed this data into computer models to improve the theory of gas adsorption." About Berkeley Lab Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit www.lbl.gov. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit the Office of Science website at science.energy.gov/. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


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Trainers of dogs, horses, and other animal performers take note: a bacterium named Moorella thermoacetica has been induced to perform only a single trick, but it’s a doozy. Berkeley Lab researchers are using M. thermoacetica to perform photosynthesis — despite being non-photosynthetic — and also to synthesize semiconductor nanoparticles in a hybrid artificial photosynthesis system for converting sunlight into valuable chemical products. “We’ve demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with cadmium sulfide nanoparticles to produce acetic acid from carbon dioxide at efficiencies and yield that are comparable to or may even exceed the capabilities of natural photosynthesis,” says Peidong Yang, a chemist with Berkeley Lab’s Materials Sciences Division, who led this work. “The bacteria/inorganic-semiconductor hybrid artificial photosynthesis system we’ve created is self-replicating through the bio-precipitation of cadmium sulfide nanoparticles, which serve as the light harvester to sustain cellular metabolism,” Yang says. “Demonstrating this cyborgian ability to self-augment the functionality of biological systems through inorganic chemistry opens up the integration of biotic and abiotic components for the next generation of advanced solar-to-chemical conversion technologies.” Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley, is the corresponding author of a paper describing this research in Science. The paper is titled “Self-photosensitization of non-photosynthetic bacteria for solar-to-chemical production.” Co-authors are Kelsey Sakimoto and Andrew Barnabas Wong. Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water. Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics. Yang and his research group have been at the forefront of developing artificial photosynthetic technologies that can realize the full potential of solar-to-chemical synthesis. “In our latest study, we combined the highly efficient light harvesting of an inorganic semiconductor with the high specificity, low cost, and self-replication and self-repair of a biocatalyst,” Yang says. “By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, we enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction.” Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an “electrograph” (meaning it can undergo direct electron transfers from an electrode), and an “acetogen” (meaning it can direct nearly 90 percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid artificial photosynthesis system. “Our hybrid system combines the best of both worlds: the light-harvesting capabilities of semiconductors with the catalytic power of biology,” Yang says. “In this study, we’ve demonstrated not only that biomaterials can be of sufficient quality to carry out useful photochemistry, but that in some ways they may be even more advantageous in biological applications.” This work was funded by the U.S. Department of Energy (DOE)’s Office of Science. The interface design part of the study was carried out the Molecular Foundry, a DOE Office Science User Facility hosted by Berkeley Lab. Release Date: January 5, 2016 Source: Berkeley Lab


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"We've demonstrated the first self-photosensitization of a non-photosynthetic bacterium, M. thermoacetica, with cadmium sulfide nanoparticles to produce acetic acid from carbon dioxide at efficiencies and yield that are comparable to or may even exceed the capabilities of natural photosynthesis," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this work. "The bacteria/inorganic-semiconductor hybrid artificial photosynthesis system we've created is self-replicating through the bio-precipitation of cadmium sulfide nanoparticles, which serve as the light harvester to sustain cellular metabolism," Yang says. "Demonstrating this cyborgian ability to self-augment the functionality of biological systems through inorganic chemistry opens up the integration of biotic and abiotic components for the next generation of advanced solar-to-chemical conversion technologies." Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoScience Institute (Kavli-ENSI) at Berkeley, is the corresponding author of a paper describing this research in Science. The paper is titled "Self-photosensitization of non-photosynthetic bacteria for solar-to-chemical production." Co-authors are Kelsey Sakimoto and Andrew Barnabas Wong. Photosynthesis is the process by which nature harvests sunlight and uses the solar energy to synthesize carbohydrates from carbon dioxide and water. Artificial versions of photosynthesis are being explored for the clean, green and sustainable production of chemical products now made from petroleum, primarily fuels and plastics. Yang and his research group have been at the forefront of developing artificial photosynthetic technologies that can realize the full potential of solar-to-chemical synthesis. "In our latest study, we combined the highly efficient light harvesting of an inorganic semiconductor with the high specificity, low cost, and self-replication and self-repair of a biocatalyst," Yang says. "By inducing the self-photosensitization of M. thermoacetica with cadmium sulfide nanoparticles, we enabled the photosynthesis of acetic acid from carbon dioxide over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical carbon dioxide reduction." Cadmium sulfide is a well-studied semiconductor with a band structure and that is well-suited for photosynthesis. As both an "electrograph" (meaning it can undergo direct electron transfers from an electrode), and an "acetogen" (meaning it can direct nearly 90-percent of its photosynthetic products towards acetic acid), M. thermoacetica serves as the ideal model organism for demonstrating the capabilities of this hybrid artificial photosynthesis system. "Our hybrid system combines the best of both worlds: the light-harvesting capabilities of semiconductors with the catalytic power of biology," Yang says. "In this study, we've demonstrated not only that biomaterials can be of sufficient quality to carry out useful photochemistry, but that in some ways they may be even more advantageous in biological applications." Explore further: Major advance in artificial photosynthesis poses win/win for the environment More information: K. K. Sakimoto et al. Self-photosensitization of nonphotosynthetic bacteria for solar-to-chemical production, Science (2015). DOI: 10.1126/science.aad3317


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There are many different ways to make nanomaterials but weaving, the oldest and most enduring method of making fabrics, has not been one of them - until now. An international collaboration led by scientists at the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, has woven the first three-dimensional covalent organic frameworks (COFs) from helical organic threads. The woven COFs display significant advantages in structural flexibility, resiliency and reversibility over previous COFs - materials that are highly prized for their potential to capture and store carbon dioxide then convert it into valuable chemical products. "We have taken the art of weaving into the atomic and molecular level, giving us a powerful new way of manipulating matter with incredible precision in order to achieve unique and valuable mechanical properties," says Omar Yaghi, a chemist who holds joint appointments with Berkeley Lab's Materials Sciences Division and UC Berkeley's Chemistry Department, and is the co-director of the Kavli Energy NanoScience Institute (Kavli-ENSI). "Weaving in chemistry has been long sought after and is unknown in biology," Yaghi says. "However, we have found a way of weaving organic threads that enables us to design and make complex two- and three-dimensional organic extended structures." Yaghi is the corresponding author of a paper in Science reporting this new technique. The paper is titled "Weaving of organic threads into a crystalline covalent organic framework." The lead authors are Yuzhong Liu, Yanhang Ma and Yingbo Zhao. Other co-authors are Xixi Sun, Felipe Gándara, Hiroyasu Furukawa, Zheng Liu, Hanyu Zhu, Chenhui Zhu, Kazutomo Suenaga, Peter Oleynikov, Ahmad Alshammari, Xiang Zhang and Osamu Terasaki. COFs and their cousin materials, metal organic frameworks (MOFs), are porous three-dimensional crystals with extraordinarily large internal surface areas that can absorb and store enormous quantities of targeted molecules. Invented by Yaghi, COFs and MOFs consist of molecules (organics for COFs and metal-organics for MOFs) that are stitched into large and extended netlike frameworks whose structures are held together by strong chemical bonds. Such frameworks show great promise for, among other applications, carbon sequestration. Through another technique developed by Yaghi, called "reticular chemistry," these frameworks can also be embedded with catalysts to carry out desired functions: for example, reducing carbon dioxide into carbon monoxide, which serves as a primary building block for a wide range of chemical products including fuels, pharmaceuticals and plastics. In this latest study, Yaghi and his collaborators used a copper(I) complex as a template for bringing threads of the organic compound "phenanthroline" into a woven pattern to produce an immine-based framework they dubbed COF-505. Through X-ray and electron diffraction characterizations, the researchers discovered that the copper(I) ions can be reversibly removed or restored to COF-505 without changing its woven structure. Demetalation of the COF resulted in a tenfold increase in its elasticity and remetalation restored the COF to its original stiffness. "That our system can switch between two states of elasticity reversibly by a simple operation, the first such demonstration in an extended chemical structure, means that cycling between these states can be done repeatedly without degrading or altering the structure," Yaghi says. "Based on these results, it is easy to imagine the creation of molecular cloths that combine unusual resiliency, strength, flexibility and chemical variability in one material." Yaghi says that MOFs can also be woven as can all structures based on netlike frameworks. In addition, these woven structures can also be made as nanoparticles or polymers, which means they can be fabricated into thin films and electronic devices. "Our weaving technique allows long threads of covalently linked molecules to cross at regular intervals," Yaghi says. "These crossings serve as points of registry, so that the threads have many degrees of freedom to move away from and back to such points without collapsing the overall structure, a boon to making materials with exceptional mechanical properties and dynamics."

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