Innovative photosynthesis hack paves way for renewable energy breakthroughs

Researchers have “hacked” the early stages of[{” attribute=””>photosynthesis, the natural machine that powers the vast majority of life on Earth, and discovered new ways to extract energy from the process, a finding that could lead to new ways of generating clean fuel and renewable energy.

An international team of physicists, chemists and biologists, led by the University of Cambridge, was able to study photosynthesis – the process by which plants, algae, and some bacteria convert sunlight into energy – in live cells at an ultrafast timescale: a millionth of a millionth of a second.

Despite the fact that it is one of the most well-known and well-studied processes on Earth, the researchers found that photosynthesis still has secrets to tell. Using ultrafast spectroscopic techniques to study the movement of energy, the researchers found the chemicals that can extract electrons from the molecular structures responsible for photosynthesis do so at the initial stages, rather than much later, as was previously thought. This ‘rewiring’ of photosynthesis could improve how it deals with excess energy, and create new and more efficient ways of using its power. The results were reported on March 22 in the journal Nature.

Although photosynthesis is a widely known and extensively studied process, University of Cambridge researchers have discovered that it still holds hidden secrets. By using ultrafast spectroscopy techniques, they found that electron extraction from the molecular structures responsible for photosynthesis occurs at earlier stages than previously assumed. This “rewiring” of photosynthesis could lead to better management of excess energy and the development of new, more efficient ways to harness its potential. Credit: Mary Ayers

“We didn’t know as much about photosynthesis as we thought, and the new electron transfer pathway we found here is quite surprising,” said Dr.

While photosynthesis is a natural process, scientists have also been studying how it could be used to help tackle the climate crisis, by simulating photosynthetic processes to generate clean fuels from sunlight and water, for example.

Zhang and her colleagues were originally trying to understand why a ring-shaped molecule called a quinone could “steal” electrons from photosynthesis. Alkenones are common in nature, and they can easily accept and give up electrons. The researchers used a technique called ultrafast transient absorption spectroscopy to study how quinones behave in photosynthetic cyanobacteria.

An international team of scientists has studied the process of photosynthesis in living cells on an ultra-fast time scale of a millionth of a millionth of a second. Despite extensive research, photosynthesis still holds undiscovered secrets. Using ultrafast spectroscopy techniques, the team discovered that chemicals extract electrons from molecular structures involved in photosynthesis at much earlier stages than previously thought. This “rewiring” can enhance the process’s handling of excess power and generate new, efficient ways to harness its power. Credit: Tommy Peake

“No one had properly studied how this molecule interacts with the mechanisms of photosynthesis at such an early stage of photosynthesis: we thought we were using a new technique to confirm what we already knew,” Zhang said. “Instead, we’ve found a completely new pathway, and we’ve opened up the black box of photosynthesis a little bit.”

Using ultrafast spectroscopy to monitor the electrons, the researchers found that the protein scaffold where the initial chemical reactions of photosynthesis occur is “leaky,” allowing electrons to escape. This seepage can help plants protect themselves from damage from bright or rapidly changing light.

“The physics of photosynthesis is incredibly impressive,” said co-first author Tomi Baikie, from the Cavendish Laboratory in Cambridge. “Normally, we work with higher-order materials, but observing charge transport through cells opens up wonderful opportunities for new discoveries about how nature works.”

said co-first author Dr Laura Way, who did the work in the Department of Biochemistry, now based at the University of Turku, Finland. “The fact that we didn’t know this pathway existed is exciting, because we can harness it to extract more energy from renewables.”

Being able to extract cargo early in the photosynthesis process, the researchers say, could make the process more efficient when manipulating photosynthetic pathways to generate clean fuel from the sun. In addition, the ability to regulate photosynthesis may mean that crops could be better able to withstand intense sunlight.

“Many scientists have tried to extract electrons from an earlier point in photosynthesis, but they said it is not possible because the energy is buried in the protein scaffold,” Zhang said. “The fact that we could steal it in an earlier operation is amazing. At first, we thought we had made a mistake: it took a while for us to convince ourselves that we had done it.”

Key to the discovery was the use of ultrafast spectroscopy, which allowed the researchers to follow the flow of energy in living photosynthetic cells on a femtosecond scale—one thousandth of a trillionth of a second.

“Using these ultra-rapid methods has allowed us to understand more about the early events in photosynthesis, on which life on Earth depends,” said co-author Professor Christopher Howe, from the Department of Biochemistry.

Reference: “Photosynthesis Rewired on a Picosecond Time Scale” by Tommy K. Paiki, Laura TY, Joshua M. Lawrence, Heights Medipaly, Erwin Reisner, Mark M. Nowaczyk, Richard H. Friend, Christopher J. Howe, Christophe Schneiderman, Akshay Rao and Jenny Zhang, Mar. 22, 2023, Available here. nature.
DOI: 10.1038/s41586-023-05763-9

The research was supported in part by the Engineering and Physical Sciences Research Council (EPSRC), the Biotechnology and Biological Sciences Research Council (BBSRC) and is part of UK Research and Innovation (UKRI), as well as the Winton Program for Sustainability Physics at the university. Cambridge, Commonwealth of Cambridge, European and International Fund, and EU Horizon 2020 Research and Innovation Programme. Jenny Zhang is the David Phillips Fellow in the Department of Chemistry, and a Fellow of Corpus Christi College, Cambridge. Tomi Baikie is a NanoFutures Fellow at the Cavendish Lab. Laura Way is a Postdoctoral Fellow at the Novo Nordisk Foundation, University of Turku.