Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ultrafast lasers reveal light-harvesting secrets of photosynthetic algae

19.12.2016

Photosynthetic algae have been refining their technique for capturing light for millions of years. As a result, these algae boast powerful light-harvesting systems -- proteins that absorb light to be turned into energy -- that scientists have long aspired to understand and mimic for renewable energy applications.

Now, researchers at Princeton University have revealed a mechanism that enhances the light harvesting rates of the cryptophyte algae Chroomonas mesostigmatica. Published in the journal Chem on December 8, these findings provide valuable insights for the design of artificial light-harvesting systems such as molecular sensors and solar energy collectors.


Researchers at Princeton University have uncovered powerful light-harvesting secrets of photosynthetic cryptophyte algae.

Credit: Desmond Toa

Cryptophyte algae often live below other organisms that absorb most of the sun's rays. In response, the algae have evolved to thrive on wavelengths of light that aren't captured by their neighbors above, mainly the yellow-green colors. The algae collects this yellow-green light energy and passes it through a network of molecules that converts it into red light, which chlorophyll molecules need to perform important photosynthetic chemistry.

The speed of the energy transfer through the system has both impressed and perplexed the scientists that study them. The Scholes lab's predictions were always about three times slower than the observed rates. "The timescales that the energy is moved through the protein -- we could never understand why the process so fast," said corresponding author Gregory Scholes, the William S. Tod Professor of Chemistry at Princeton University.

In 2010, Scholes' team found evidence that the culprit behind these fast rates was a strange phenomenon called quantum coherence, in which molecules could share electronic excitation and transfer energy according to quantum mechanical probability laws instead of classical physics. But the research team couldn't explain exactly how coherence worked to speed up the rates until now.

Using a sophisticated method enabled by ultrafast lasers, the researchers were able to measure the molecules' light absorption and essentially track the energy flow through the system. Normally the absorption signals would overlap, making them impossible to assign to specific molecules within the protein complex, but the team was able to sharpen the signals by cooling the proteins down to very low temperatures, said Jacob Dean, lead author and postdoctoral researcher in the Scholes lab.

The researchers observed the system as energy was transferred from molecule to molecule, from high-energy green light to lower energy red light, with excess energy lost as vibrational energy. These experiments revealed a particular spectral pattern that was a 'smoking gun' for vibrational resonance, or vibrational matching, between the donor and acceptor molecules, Dean said.

This vibrational matching allowed energy to be transferred much faster than it otherwise would be by distributing the excitation between molecules. This effect provided a mechanism for the previously reported quantum coherence. Taking this redistribution into account, the researchers recalculated their prediction and landed on a rate that was about three times faster.

"Finally the prediction is in the right ballpark," Scholes said. "Turns out that it required this quite different, surprising mechanism."

The Scholes lab plans to study related proteins to investigate if this mechanism is operative in other photosynthetic organisms. Ultimately, scientists hope to create light-harvesting systems with perfect energy transfer by taking inspiration and design principles from these finely tuned yet extremely robust light-harvesting proteins. "This mechanism is one more powerful statement of the optimality of these proteins," Scholes said.

###

Read the full article here:

Dean, J. C.; Mirkovic, T.; Toa, Z. S. D.; Oblinsky, D. G.; Scholes, G. D. "Vibronic Enhancement of Algae Light Harvesting." Chem 2016, 1, 858.

This work was supported as part of the Photosynthetic Antenna Research Center, an Energy Frontier Research Center funded by the Basic Energy Sciences program of the US Department of Energy Office of Science under award DE-SC0001035.

Media Contact

Tien Nguyen
tienn@princeton.edu
609-258-6523

 @Princeton

http://www.princeton.edu 

Tien Nguyen | EurekAlert!

More articles from Life Sciences:

nachricht New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences

nachricht The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>