Scientists involved in the Glasgow Solar Fuels project at Glasgow University in Scotland recently revealed at the American Association for the Advancement of Science annual meeting in Vancouver (Canada) that they had made a breakthrough in making biofuels more efficiently using electricity rather than sunlight, which is normally used in the case of algae or bacteria-based biofuels.
The team led by Professor Richard Cogdell has been studying photosynthetic organisms that have evolved light-harvesting complexes to concentrate solar energy and accumulate enough charge to perform catalytic reactions such as water splitting and CO2 fixation.
The team now plans on capitalising on its experience of the biological apparatus of this photosynthesis and expertise in structural biology and synthetic chemistry by applying the design principles of the natural system described above to build artificial complexes capable of harvesting solar energy and separating and storing charges.
“The unique feature of our proposal is that we intend to use state-of-the art lithographic techniques to immobilise the various components on a surface. By controlling the spatial relationship between light-harvesting (LH2 and the RC-LH1), electron transport and catalytic sites in this way, we aim to mimic the role of the thylakoid membrane and so generate a solid-state Artificial Photosynthetic Unit (aPSU),” says the team on its website. “Ultimately, we aim to couple these reaction centres to catalytic centres capable of splitting water and reducing CO2, yielding methanol as a fuel.”
The team describe its technology as an “electric leaf”, which has been developed by genetically modifying these photosynthetic bacteria to make the liquid hydrocarbon. Unlike other natural biofuel production processes, such as those using algae, the electric leaf draws its energy from electricity generated from renewable sources such as wind or sun, not directly from solar radiation.
“The problem with photosynthesis is that it is extremely inefficient – its maximum efficiency [for turning solar energy into biomass] is 4 per cent and in most plants it is about 0.5 per cent,” Professor Cogdell told the Financial Times recently. “We think we can do much better by taking electricity from a renewable source and using that to drive the reaction.”
The Glasgow Solar Fuels project received a £3 million grant from the Engineering and Physical Sciences Research Council and the UK Biotechnology and Biological Sciences Research Council.
“They have been very brave to fund this ‘blue sky’ project,” Professor Cogdell told the Financial Times. But if it succeeds, the pay-off would be enormous, he added, because “one of the grand challenges that mankind faces is to make dense, portable fuels for transport from non-carbon sources.”
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