IMPERIAL researchers have solved the structure of the molecular reaction centre that plants use to split water during photosynthesis.

Imperial scientists visualise the water-splitting centre in photosynthesis

The team led by Professor So Iwata and Professor Jim Barber, department of biological sciences, suggest visualising the centre provides an insight into a possible method of producing a cheap supply of hydrogen in the future.

"Researchers have investigated using electrolysis to split water into oxygen and hydrogen but today it costs 10 times as much as natural gas, and is three times as expensive as gasoline," explained Professor Jim Barber, department of biological sciences.

"Yet nature figured out how to split water using sunlight in an energy efficient way 2.5 billion years ago. By revealing the structure of the water splitting centre, we can begin to unravel how to perform this task in an energy efficient way too."

Photosynthesis occurs in plants, some bacteria and algae and involves two protein complexes, photosystem I, and photosystem II, which contains the water-splitting centre.

Using X-ray crystallography, the researchers, who reported their findings in Science and include co-authors Kristina Ferreira, Tina Iverson and Karim Maghlaous, have described for the first time the mechanism that underpins the photosynthetic water-splitting reaction. Recreating the process on an industrial scale would allow hydrogen to be manufactured as a fuel.

"Without photosynthesis, life on Earth would not exist as we know it. Oxygen derived from this process is part of the air we breathe and maintains the ozone layer needed to protect us from UV radiation," Professor Barber continued.

"Now hydrogen also contained in water could be one of the most promising energy sources for the future.

"Unlike fossil fuels it's highly efficient, low polluting and is mobile so it can be used for power generation in remote regions where it's difficult to access electricity.

"Manufacturing hydrogen from water using the photosynthetic method would be far more efficient than using electrolysis.

"If we can learn how to use even a fraction of the 326 million cubic miles of water on the planet, we can begin to address the world's pressing need for new and environmentally friendly energy sources."