Biologist Anja Hemschemeier researches green algae. Photo Credit: RUB, Marquard |
Old yellow enzymes have been known for almost 100 years, but their function for organisms is largely in the dark. A Bochum research team publishes initial findings on microalgae.
Old yellow enzymes, or OYEs for short, from the English Old Yellow Enzymes, were discovered in the 1930s and have been heavily researched since then. Because these biocatalysts - colored yellow by an auxiliary molecule - can carry out reactions that are very valuable for the chemical industry, such as pre-medication or fragrance substances. Although OYEs are found in many organisms, their natural role for these living beings is hardly known - possibly because the scientific focus was on biotechnological use. Researchers around private lecturer Dr. Anja Hemschemeier and Prof. Dr. Thomas Happe from the Ruhr University Bochum now shows that an OYE of the unicellular green algae Chlamydomonas reinhardtii is important for the vegetable unicellular organism to protect itself from light stress. The researchers published their results in the journal "Plant Direct" from 15. Published January 2023.
OYEs in microalgae use energy from photosynthesis
"Our working group is one of the first to investigate OYEs in algae," says Dr. Stefanie Böhmer, first author of the study. “First of all, we wanted to investigate whether these biocatalysts are also suitable for industrial processes. It was particularly interesting for us whether microalgae can use the energy of photosynthesis to drive the corresponding chemical reactions. This could help establish more environmentally friendly productions. "The researchers were able to prove this: A chemical molecule added to living algae cells was only implemented in light at high rates. "However, this result also indicated that the so-called en-reductases in the algae responsible for this are related to photosynthesis," said Böhmer. Therefore, the scientists of the photobiotechnology working group examined how an algae strain in which an OYE biocatalyst is defective adapts to heavy light.
Excess light energy must be derived
In fact, the Bochum research team, in cooperation with researchers from the University of Leipzig, was able to show that this algae strain is hardly able to dissipate excess light energy. "Photosynthetic organisms such as algae and plants must always maintain the balance between absorbed light energy and its conversion into chemical energy," explains Anja Hemschemeier, under whose leadership the study was carried out. “If the light is too strong, there is otherwise oxidative cell damage. Therefore, these living beings have pronounced protective mechanisms to dissipate excess light energy, for example as heat."
In the microalgae strain that lacks an OYE, the researchers were barely able to demonstrate these protective mechanisms, and the strain accordingly showed oxidative damage. "We suspect that a particular molecule that is normally converted into the algae cells by this biocatalyst is important for the photosynthetic balance," said Hemschemeier.
The research team now wants to get to the bottom of this. “Photosynthetic organisms are the basis for our lives. It is very important to understand how they adapt to stress conditions and we believe that we have found another piece of the puzzle here,” concludes Hemschemeier.
Published in journal: Plant Direct
Source/Credit: Ruhr University Bochum
Reference Number: bio011823_01