Spinach gave Popeye superpowers, but it also held the promise of an entirely different kind of energy for a group of scientists: the ability to convert the sun's rays into a clean and efficient alternative fuel.
Spinach gave Popeye superpowers, but it also held the promise of an entirely different kind of energy for a group of scientists: the ability to convert the sun's rays into a clean and efficient alternative fuel.
Artificial photosynthesis processes could enable the conversion of solar energy into hydrogen-based fuels that would be both renewable and environmentally friendly. Physicists from Purdue University are part of an international group of researchers using spinach to study the proteins involved in photosynthesis, the process through which plants convert solar energy into carbohydrates used to supply energy in cellular processes.
"The proteins we are studying are part of the most efficient system ever built, one capable of converting solar-derived energy into chemical energy with an unrivaled conversion efficiency of 60%," said Yulia Pushkar, a physics professor associated with the study. "Understanding this system is particularly important in the field of alternative energy research aimed at the development of artificial photosynthesis systems."
During photosynthesis, plants use the sun's energy to convert carbon dioxide and water into carbohydrates that contain hydrogen and oxygen. Artificial photosynthesis systems could enable the conversion of solar energy into hydrogen-based fuels that would be both renewable and environmentally friendly. In the researchers' laboratory, the scientists were able to extract a protein conjugate known as photosystem II from spinach purchased at the grocery store. The extraction process is a complex process that lasts two whole days in a specially built room that keeps the spinach samples protected from sunlight and under cooling conditions. After the proteins were carefully extracted from the plant, the researchers stimulated them with a laser and recorded the changes in the electron configurations of their molecules. "These proteins need light in order to function, so our laser functions as the sun in this experiment," said the lead researcher. "From the moment the proteins begin to act, we use advanced techniques such as paramagnetic resonance of electrons and X-ray spectroscopy in order to observe how the electron structure of the molecules changes over time while they perform their action."
Photosystem II is involved in the photosynthetic apparatus that converts water molecules into oxygen, protons and electrons. In this process, the part of the protein coupling known as the 'oxygen progression coupling' goes through five stages at the end of which 4 electrons are removed, explains the researcher. The international team recently revealed the structure of the first and third states at a resolution of 5 and 5.5 angstroms, respectively, using an innovative method known as 'serial femtosecond crystallography'. An article describing the research findings was recently published in the scientific journal Nature.
"The trick is to use the most powerful X-ray laser in the world, known as LCLS, located at the Department of Energy's National Accelerator Laboratory," said one of the scientists involved in the study. "Extremely fast laser pulses at the rate of a femtosecond (a quadrillionth of a second, a thousandth of a nanosecond) make it possible to take snapshots of photosystem II crystals immediately before they break apart in an explosion as a result of the X-ray beam, a principle known as 'breakdown before destruction' '.
While X-ray crystallography reveals the structural changes, the method does not provide details about how the electron configurations change over time, a gap that the Purdue University researchers are trying to fill. The research team imitated the conditions of a serial femtosecond crystallographic experiment, but using electron paramagnetic resonance, explains the lead researcher. "The electronic arrays are used to verify what is the stage within the photosystem II process at a given time," she explains. "This information is a kind of time stamp without which the research team could not put the structural changes into the correct context of the overall process."
(Translated by Dr. Moshe Nachmani)
On the same topic on the science website: Popeye the salt would be disappointed - spinach has a lot of iron, but also a substance that prevents its digestion
Will personal computers be able to run on spinach? (article from 2004)
One response
All the nonsense of biodiesel from plants, algae, bacteria... has been an unrealistic dream for many years, it's a shame that money continues to be wasted on it.
Only nuclear or thermonuclear energy (in the future) is cheap, does not harm the environment, reliable and realistic.