From a forwarded message at
Ocean photosynthesis: Unlimited fuel source potential
28 March 2004
Provider: Deutsche Presse-Agentur (dpa)
London (dpa) - Artificial photosynthesis could turn the world's
oceans into a potentially boundless source of fuel, scientists
recently reported in London, citing new research about the mechanism
which plants use to break up water into oxygen and hydrogen.
Photosynthesis converts carbon dioxide in the atmosphere into organic
matter and oxygen by using sunlight to break the chemical bond
holding the constituents of water together.
At Imperial College London, scientists said they were now looking at
one fine detail of the protein complex that drives the process,
hoping that a way may be found to copy photosynthesis on an
"Without photosynthesis life on Earth would not exist as we know it,"
commented professor Jim Barber, from Imperial's department of
biological sciences. "Oxygen derived from this process is part of the
air we breathe and maintains the ozone layer needed to protect us
from UV (ultraviolet) radiation.
"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," he added.
The problem was that hydrogen bond with oxygen in former water is a
very stable bond, one not easily broken apart. Barber said
researchers were investigating the use of electrolysis to split
water. However, fuel made this way would cost 10 times as much as
natural gas and three times as much as gasoline.
"Yet nature figured out how to split water using sunlight in an
energy efficient way 2.5 billion years ago," Barber said. "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 involves two protein complexes, photosystem I, and
photosystem II. The second of these, PSII, contains the water-
splitting machinery. Using a light scattering technique called X-ray
crystallography, the scientists revealed the structure of PSII to a
resolution of a hundred millionth of a centimetre.
They found it contained manganese, calcium and oxygen atoms in a cube-
like arrangement, which provided strong clues about the water-
"If we can learn 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,"
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