Scientists from the University of Southampton (UK) have reengineered the fundamental process of photosynthesis to power useful chemical reactions that could be used to produce biofuels, pharmaceuticals, and fine chemicals. Photosynthesis is the pivotal biological reaction on the planet, providing the food we eat, the oxygen we breathe, and removing CO2 from the atmosphere. Photosynthesis in plants and algae consists of two reactions, the light-reactions absorb light energy from the sun and use this to split water (H2O) into electrons, protons, and oxygen, and the dark-reactions which use the electrons and protons from the light reactions to “fix” CO2 from the atmosphere into simple sugars that are the basis of the food chain. Importantly, the light reactions have a much higher capacity than the dark reactions resulting in much of the absorbed light energy being wasted as heat rather than being used to “fix” CO2. Co-author Dr. Adokiye Berepiki, a Postdoctoral Research Fellow from Ocean and Earth Sciences at the University of Southampton, said: "In our study, we used synthetic biology methods to engineer an additional enzyme in-between the light-reactions and before the dark-reactions. We have therefore 'rewired' photosynthesis such that more absorbed light is used to power useful chemical reactions. This study therefore represents an innovation whereby a range of additional valuable chemical reactions can be powered by the sun in plants and algae." In the study, published online on July 20, 2016 in ACS Synthetic Biology, the “wasted” electrons were rewired to degrade the widespread environmental pollutant atrazine (a herbicide used in agriculture). Atrazine was banned from the EU over 20 years ago, but is still one of the most prevalent pesticides in groundwater.
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