Algae Carbon Flow Controlled by Changing Light Colors

Blue and red light-sensing photoreceptors can be used to control the carbon flow in diatoms, a major group of algae that generates about one-fourth of the Earth’s oxygen and perform around a quarter of global CO₂ assimilation.

Researchers from Leipzig University and the Helmholtz Center for Environmental Research made the findings, which they said show that cultures pre-acclimated to blue light and red light exhibited similar growth performance, photosynthesis rates and metabolite profiles.

Optical micrograph of a diatom. Courtesy of Christian Wilhelm/Leipzig University.

“Diatoms display a special way of reacting to light and adapting their metabolism to the changing light conditions in the water,” said Dr. Christian Wilhelm, a professor and head of the Plant Physiology Department at Leipzig. “For the first time we have been able to show that the light receptors, which measure the intensity of the blue or red light, not only change the genetic transcription, but also directly control the activity of enzymes in the metabolism.”

In the study, the work revealed “rapid and severe changes in the metabolite profile within 15 minutes of the initial reaction of light acclimation,” the researchers wrote in the study. They also found that the rapid change from blue to red light, and vice versa, does not influence the photosynthesis output.

“This way, cells that have grown in red light, which continue to be cultivated in a blue light environment, can still perform photosynthesis but can no longer grow,” Wilhelm said.

Via a MetaPro metabolomic platform, the team found that such switches in light allowed them to control the carbon flow in cells. This could lead to new methods to further control biotechnological cells.

This recent study comes after similar work by the group, published in Biosource Technology (doi: 10.1016/j.biortech.2012.06.120) in 2012. There, the team was able to prove that sunlight could be converted into pure natural gas in a highly efficient manner with the aid of micro-organisms. In doing so, the metabolism of green algae was reversed.

The most recent study was published in PLOS One (doi:10.1371/journal.pone.0099727).

For more information, visit www.zv.uni-leipzig.de.