New discovery reveals how diatoms capture carbon dioxide so effectively

Tiny ocean diatoms are powerful carbon-capture agents, fixing up to 20% of Earth's CO₂. A team at the University of Basel, led by Prof. Ben Engel, discovered that a special protein shell in diatoms, called the PyShell, is essential for their effective CO₂ fixation. This breakthrough could inspire new bioengineering strategies to combat atmospheric CO₂.

Diatoms play a critical role in the carbon cycle, using photosynthesis to absorb CO₂ and produce nutrients that sustain much of ocean life. Yet, the mechanics of their efficient CO₂ capture have been largely unknown. Working with colleagues from the University of York and Kwansei-Gakuin University, researchers used advanced cryo-electron tomography (cryo-ET) to study the PyShell, revealing its role in shaping diatom pyrenoids, where CO₂ is highly concentrated and fixed by the enzyme Rubisco.

When the PyShell was removed, CO₂ fixation and photosynthesis in diatoms slowed significantly, underlining the PyShell’s importance in carbon capture. This discovery could inspire CO₂-reducing bioengineering solutions. Prof. Engel hopes this research will ultimately support technologies that enhance CO₂ capture in plants or algae, helping to slow climate change. This research underscores the value of basic science for innovative climate solutions.