Researchers document key processes of photosynthesis

This could eventually lead to improved and cheaper biofuels.

In a major breakthrough researchers have for the first time been able to capture the exact set of chemical reactions that make a photosynthesis.

The discovery proves that the chemical reactions which strip electrons from water and thus initiate the conversion of solar energy into chemical energy, happens much faster than previously envisaged.

“We can now see how nature has optimized the physics of converting light energy to fuel,” said Jasper van Thor, the lead author of the study.

The discovery could lead scientists to artificially create photosynthesis so as to produce biofuels more efficiently.

Researchers from Britain’s Imperial College London were able to figure out exactly how quickly the Photosystem II enzyme reaction works.

Previously, the process which splits water into oxygen and hydrogen, was thought to be the bottleneck – the slowest part of the photosynthesis. In contrast the first part of photosynthesis, wherein light is harvested by an “antenna complex” of proteins and clorophyll molecules, was envisaged to be the fastest.

It is to be understood that the terms slow and fast are used in relative terms here, because both processes actually occur in matters of picoseconds – one trillionth of a second.

In order to measure the reactions precisely, scientists first created crystals of the Photosystem II enzyme. They then zapped them with a laser system. This entire system was done in collaboration with the University of Wisconsin-Milwaukee.

In case you are interested in reading the earlier paper, click here.

In order to see when exactly the energy transfer took place, the team of researchers used infrared spectroscopy to measure electron movements across tiny parts of the system.

This is when they realized that the splitting of hydrogen and oxygen from water happens more quickly than the antenna complex light harvesting process.

The results have turned decades of teachings on their head.

“We can now show that what I was lectured as an undergraduate in the 1990s is no longer supported,” said van Thor.

The researchers have now created a movie which documents key parts of the photosynthesis process which is just a few nanoseconds long.

The movie will help scientists and students better understand what the molecule is doing in very small time slices during the photosynthesis process.

“Can we mimic it or tune it to make artificial photosynthesis more efficient? These questions, and many others, can now be explored,” said van Thor.


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