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In the past 50 years, cytochrome P450 monooxygenases (P450s) have been given significant attention for the synthesis of natural products (e.g., vitamins, steroids, lipids) and pharmaceuticals. Despite their potential, however, costly nicotinamide cofactors such as NAD(P)H are required as reducing equivalents; thus, in situ regeneration of NAD(P)H is essential to sustaining P450-catalyzed reactions. Furthermore, poor stability of P450s has been considered as a hurdle, hampering industrial implementations of P450-catalyzed reactions. Herein we describe the development of an economic and robust process of P450-catalyzed reactions by the combination of P450 immobilization and solar-induced NADPH regeneration. The P450 monooxygenase could be efficiently immobilized on a P(3HB) biopolymer, which enabled simple purification from the E. coli host. We clearly demonstrated that the P450-P(3HB) complex exhibited much higher enzymatic yield and stability than free P450 did against changes of pH, temperature, and concentrations of urea and ions. Using the robust P450-P(3HB) complex and solar-tracking module, we successfully conducted P450-catalyzed artificial photosynthesis under the irradiation of natural sunlight in a preparative scale (500 mL) for multiple days. To the best of our knowledge, this is the largest reactor volume in P450-catalyzed reactions reported so far. We believe that our robust platform using simple immobilization and abundant solar energy promises a significant breakthrough for the broad applications of cytochrome P450 monooxygenases.

Organic Farming Could Feed the World, But..

Ted Sargent to give Seminar at the Joint Center for Artificial Photosynthesis (JCAP) Sept

15/11/2017 · What about Ricin, Unc

(The CO can then be converted into hydrocarbon fuels through an established industrial process called Fischer-Tropsch synthesis.) Zhang, who contributed to the work while a post-doctoral fellow at U of T and is now a professor at Fudan University, said, "Over the last couple of years, our team has developed very high-performing catalysts for both the first and the second reactions. “But while the second catalyst works under neutral conditions, the first catalyst requires high pH levels in order to be most active." That means that when the two are combined, the overall process is not as efficient as it could be, as energy is lost when moving charged particles between the two parts of the system. The team has now overcome this problem by developing a new catalyst for the first reaction — the one that splits water into protons and oxygen gas. Unlike the previous catalyst, this one works at neutral pH, and under those conditions it performs better than any other catalyst previously reported. Zheng, who is now a postdoctoral scholar at Stanford University, said, "It has a low overpotential, which means less electrical energy is needed to drive the reaction forward. “On top of that, having a catalyst that can work at the same neutral pH as the CO₂ conversion reaction reduces the overall potential of the cell." In the paper, the team reports the overall electrical-to-chemical power conversion efficiency of the system at 64 percent. According to De Luna, this is the highest value ever achieved for such a system, including their previous one, which only reached 54 percent. The new catalyst is made of nickel, iron, cobalt and phosphorus, all elements that are low-cost and pose few safety hazards. It can be synthesized at room temperature using relatively inexpensive equipment, and the team showed that it remained stable as long as they tested it, a total of 100 hours. Armed with their improved catalyst, the Sargent lab is now working to build their artificial photosynthesis system at pilot scale. The goal is to capture CO₂ from flue gas — for example, from a natural gas-burning power plant — and use the catalytic system to efficiently convert it into liquid fuels. De Luna said, "We have to determine the right operating conditions: Flow rate, concentration of electrolyte, electrical potential. "From this point on, it's all engineering." The team and their invention are semi-finalists in the NRG COSIA Carbon XPRIZE, a $20 million challenge to develop breakthrough technologies that will convert CO?

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For hydrogen generation, a molecule is needed to absorb photons and transfer electrons to a , which in turn transfers the electrons to the water molecules’ protons, producing hydrogen. Unfortunately, in many of the artificial photosynthesis schemes that have been tried, this light-absorbing molecule decomposes quickly. Two days has been the upper limit for systems that use organic dyes or compounds containing metals like iridium as photosynthesizers. To overcome the decomposition problem, researchers looked to semiconductor nanocrystals. These are more stable, but those tested so far have produced little hydrogen.

The artificial photosynthesis system lasted for about 15 days and converted more than ..
A new catalyst created by U of T Engineering researchers brings them one step closer to artificial photosynthesis ..

supervision of Professor Ted Sargent of The ..

Harnessing solar energy has recently attracted much attention due to the increased importance of environmental and energy issues. In particular, the photolysis of water using photocatalysts, so called artificial photosynthesis, has been receiving great attention in terms of the direct and efficient solar energy conversion system to produce O2 and H2 as chemical fuels. The effectiveness of water splitting using photocatalysts is determined by the utilization of visible light of the solar spectrum, capacity of the harvested light to generate charge carriers, and the extent of charge separation and transfer. Thus, the selection of semiconducting photocatalyst materials with proper band position, bandgap energy, and long-lived stability is critical for the viable water splitting system. Herein we report on the synthesis of highly porous, 1-D tungsten-doped BiVO4 nanofibers (W:BiVO4 NFs). To facilitate photocatalysis, we introduced nickel nanoparticles (NiOx NPs) as co-catalysts on the surface of the W:BiVO4 NFs. The outstanding water oxidation performance of the NiOx NPs-functionalized W:BiVO4 NFs were obtained through (i) the control of polymer/precursor to achieve porous W:BiVO4 NFs (for higly increased surface area), (ii) the control of tungsten-doping level (for fast charge transfer), and (iii) the optimization of the loading amounts of NiOx NPs (for efficient charge pathway suppression of charge recombination).

21/11/2017 · A new catalyst created by U of T Engineering researchers brings them one step closer to artificial photosynthesis ..

Improving on Artificial Photosynthesis Design | LinkedIn

Researchers from the University of Illinois at Chicago have constructed an artificial leaf that captures sunlight and uses it to convert carbon dioxide in the atmosphere to usable hydrocarbon fuel. Senior author on the study, Amin Salehi-Khojin assistant professor of mechanical and industrial engineering, notes that “the new solar cell is not photovoltaic — it’s photosynthetic.” Using a combination of intricately engineered nano-membranes and unique combinations of catalytic molecules the artificial leaf takes in sunlight and CO2 and produces syngas or synthetic gas (hydrogen and carbon monoxide gas) from the cathode, and free oxygen and hydrogen ions at the anode.

21/06/2016 · Improving on Artificial Photosynthesis Design

major advance toward synthetic photosynthesis, ..

Fujitsu claims, the use some advanced materials is increasing the effeciency of production of oxygen in Artificial Photosynthesis using sunlight and water by nearly 100-fold.To artificially produce storable energy in the form of hydrogen and organic compounds requires extraction of reaction electrons from a photocatalyst material using light source and electrode that help in efficiently reacting with water or CO2. Earlier, semiconductor materials and relatively coarse-grained photocatalyst materials have been used in low-density rigid structures for the photo reactive electrodes where sunlight and water react. But the issue with that was the usable wavelengths of light in sunlight (visible light) fall in a narrow range and was difficult to achieve sufficient current flow from the chemical reaction.Fujitsu could change that by using a thin film technology. Fujitsu has improved the methods of forming thin films (nano particle deposition of electroceramics on flexible mounting sheets to create capacitors or other passive components). To develop a process technology for layering thin films on a substrate, Fujitsu' developers have used a nozzle to spray the photocatalyst-material particle that fragments the particle on a thin plate.The key features Fujitsu explains are as follows:1. Fujitsu could expand usable wavelength of sunlight so that sunlight is very well utilized for this purpose.After creating a film of the raw-material photocatalyst-material particle, it is formed into a crystalline structure having deviation at the molecular level, which broadens the spectrum of sunlight that can be absorbed from a maximum wavelength of 490nm using existing technology to 630nm with this technology, more than doubling the usable sunlight that is captured.2. The film what Fujitsu has used had a good crystalline structure lacking in macro- or micro-level flaws, and precisely formed structure with high electrical conductivity between the particles in the material. This enables electrons electrically excited by photons in sunlight to be efficiently transmitted to the electrodes.3. A structure formed of nano-sized particles ensures a large surface area. Due to this new technique, Fujitsu can increase the surface area so that it can react with water could react with more surface area.4. The crystalline surface for systematically structured to boosts electron density throughout the material's crystal structure.This promoted higher interaction between water and sunlight.Benefits include doubling the usable amount of light which is increased by light a factor of 50 the surface area of the material that can react with water. All together, given advantage where the research report confirm to increase the efficiency in producing electricity and oxygen by more than a factor of 100 claims Fujitsu.Fujitsu is continuing its research to develop this technology further.