It seems that we will have to come to terms with the new idea of ??the basic mechanism of photosynthesis and rewrite biology textbooks. The fact is that scientists have discovered a new type of photosynthesis. The vast majority of life on Earth uses visible red light in the process of photosynthesis, but the new type uses near infrared light. It was found in a wide range of cyanobacteria (blue-green algae) that grow in near infrared light, in darkened conditions in Yellowstone and on stone beaches in Australia. As scientists at Imperial College London found out, this also happens in a cabinet with infrared LEDs.

Photosynthesis beyond the red limit

The usual, almost universal type of photosynthesis uses the green pigment chlorophyll A, both to absorb light and to use its energy to produce useful biochemical substances and oxygen. Chlorophyll absorbs light in such a way that only red light energy can be used for photosynthesis.

Since chlorophyll A is present in all plants, algae, and cyanobacteria that we know, it was believed that the red light energy sets the “red limit” for photosynthesis, with respect to the minimum amount of energy needed to perform the complex chemistry that produces oxygen. However, when some cyanobacteria were grown under near infrared light, standard systems containing chlorophyll A were turned off and allowed other systems containing another type of chlorophyll to work, chlorophyll F.

Until today, it was believed that chlorophyll F only collects light. A new study showed that under darkened conditions, chlorophyll F is involved in photosynthesis, using low-energy infrared light for complex chemical reactions.

Professor Bill Rutherford of the Department of Life Sciences says: “A new form of photosynthesis has forced us to rethink what we considered the standard. We also reviewed key events in the heart of ordinary photosynthesis. We’ll have to rewrite textbooks. ”

Light damage prevention

Cyanobacteria Acaryochloris has long been known for carrying out photosynthesis beyond the red limit. But since this occurs only in one species with a very specific habitat, it was considered an exception. Acaryochloris lives under green sea ascidia and receives almost no light.

Chlorophyll F photosynthesis is a widespread third type of photosynthesis. However, it is used only in special darkened conditions, rich in infrared light.

It was believed that light damage would be more serious beyond the red limit, but a new research showed that this was not a problem for stable shaded conditions.

Andrea Fantuzzi, one of the authors of the work, believes that “the discovery of a type of photosynthesis that works beyond the red limit changes our understanding of the energy requirements for photosynthesis." It sheds light on the use of the light energy and the mechanisms that protect systems from light damage."

Dr. Dennis Nuremberg, the first author and initiator of the research said the following: “I didn't expect that my interest in cyanobacteria and their diverse lifestyle would lead to serious changes in our understanding of photosynthesis. It's amazing how much more in nature awaits discovery.”