New Type of Photosynthesis Discovered

A new type of photosynthesis has been discovered by an international team of scientists. The discovery, led by Imperial College London, and involved groups from Australia and France changes the understanding of basic mechanism of photosynthesis.

Photosynthesis uses visible red light, but the new type uses near-infrared light instead. It was detected in a wide range of cyanobacteria (blue-green algae) when they grow in near-infrared light, found in shaded conditions like bacterial mats in Yellowstone and in beach rock in Australia. Scientists have discovered that it also occurs in a cupboard fitted with infrared LEDs in Imperial College London.

Photosynthesis uses chlorophyll-a, both to collect light and make useful biochemicals and oxygen. The way chlorophyll-a absorbs light means only the energy from red light can be used for photosynthesis. Chlorophyll-a is present in all known plants, algae, and cyanobacteria. Red light's energy sets the ‘red limit' for photosynthesis, which is the minimum amount of energy needed to produce oxygen. However, when some cyanobacteria are grown under near-infrared light, the standard chlorophyll-a-containing systems shut down and different systems containing a different kind of chlorophyll, chlorophyll-f, takes over.

Lead researcher Professor Bill Rutherford from the Department of Life Sciences at Imperial said, "The new form of photosynthesis made us rethink what we thought was possible. It also changes how we understand the key events at the heart of standard photosynthesis. This is textbook changing stuff."

For more details, read the news article from Imperial College London.