nitrogen without sacrificing photosynthetic efficiency.
In natural photosynthesis, solar energy is converted to chemical energy through a cascaded, photoinduced charge transfer chain that consists of primary and secondary acceptor quinones (i.e., QA and QB), which leads to exceptionally high quantum yield near unity. Inspired by the unique multistep charge transfer architecture in nature, we have synthesized catecholamine-functionalized, reduced graphene oxide (RGO) film as a redox mediator that can mimic quinone acceptors in the photosystem II. We utilized polynorepinephrine (PNE) as a redox-shuttling chemical, as well as to coat graphene oxide (GO) and to reduce GO to RGO. The two-electrons-and-two-protons-involving charge transfer characteristic of quinone ligands in PNE acted as an electron acceptor that facilitated charge transfer in photocatalytic water oxidation. Furthermore, PNE-coated RGO film promoted fast charge separation in [Ru(bpy)3]2+ and over two-fold increased the activity of cobalt phosphate on photocatalytic water oxidation. The results suggest that our bio-inspired strategy for the construction of forward charge transfer pathway can provide more opportunities to realize efficient artificial photosynthesis.
Mr G’s Environmental Systems » 1.1. 3: Energy in Systems
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.
Green conversion of carbon dioxide to fuels has attracted high interest recently due to the global issues of environmental sustainability and renewable energy sources. In this study, we present photoelectrochemical (PEC) regeneration of nicotinamide cofactors (NADH) coupled with enzymatic synthesis of formate from CO2 towads mimicking natural photosynthesis. The water oxidation-driven PEC platform exhibited high yield and rate of NADH regeneration compared to many other homogeneous, photochemical systems. We successfully coupled solar-assisted NADH reduction with enzymatic CO2 reduction to formate under continuous CO2 injection.
Pigments for Photosynthesis - HyperPhysics Concepts
The breakthrough, "", published in the journal Science, lead by researcher Prof Stephen Long, based at the University of Illinois and the University of Lancaster, shows decades of research into the 140-step process by which plants convert sunlight energy into food revealed specific "inefficiencies in crops". There are bottlenecks holding up the conversion of sunlight energy into food. Long and his team tackled one of those bottlenecks. Which led to increased yield in an experimental crop by 15%.
Water-use efficiency - Wikipedia
In green plants, solar-powered electrons are transferred through sophistically arranged photosystems and are subsequently channelled into the Calvin cycle to generate chemical energy. Inspired by the natural photosynthetic scheme, we have constructed a photoelectrochemical cell (PEC) configured with protonated graphitic carbon nitride (p-g-C3N4) and carbon nanotube hybrid (CNT/p-g-C3N4) film cathode and FeOOH-deposited bismuth vanadate (FeOOH/BiVO4) photoanode for the production of industrially useful chiral alkanes using an old yellow enzyme homologue from Thermus scotoductus (TsOYE). In the biocatalytic PEC platform, photoexcited electrons provided by the FeOOH/BiVO4 photoanode are transferred to the robust and self-standing CNT/p-g-C3N4 hybrid film that electrocatalytically reduces flavin mononucleotide (FMN) mediator. The p-g-C3N4 promoted a two-electron reduction of FMN coupled with an accelerated electron transfer by the conductive CNT network. The reduced FMN subsequently delivered the electrons to TsOYE for the highly enantioselective conversion of ketoisophorone to (R)-levodione. Under light illumination (> 420 nm) and external bias, (R)-levodione was synthesized with the enantiomeric excess value of above 83%, not influenced by the scale of applied bias, simultaneously exhibiting stable and high current efficiency. Our results suggest that the biocatalytic PEC made up of economical materials can selectively synthesize high-value organic chemicals using water as an electron donor.
Symposium | Tropical Agriculture Conference
CONCLUSION: Since 2007 research has shown that quantum coherence is functional in increasing the efficiency of energy transfer in photosynthetic systems, including multicellular plants at room temperature. What has never been emphasised in discussions about this type of research is that similar systems to those utilising quantum coherence in plants are also present, in the form of mitochondria, in animal cells including neurons. Evolution has a tendency to retain features, so there is no reason to believe that it would not have retained the ability to utilise quantum coherence in animal cells, and thus in neurons. The intensive activity and integration involved in conscious processing thus looks a prime candidate for the more efficient energy transfer offered by quantum coherence.