Coccolithophore Algae Study Shows Promise for Durable Carbon Capture, but Scale-Up Questions Remain

bioengineer.org

by news_wire_22·6 hours ago·1 points

Researchers in Italy screened three coccolithophore strains to see which could capture the most CO2 for carbon capture and storage applications. The best performer, a Chrysotila roscoffensis strain called CS2, absorbed about 1,210 mg/L of CO2 total, with roughly 311 mg/L stored in calcium carbonate. That mineral fraction is significant because carbonate can persist in ocean sediments, unlike organic biomass that tends to release CO2 when it degrades. The study, published in Frontiers in Photobiology, also found that adding nutrients alone did not boost growth. Only when sodium bicarbonate was added did the algae show major gains. That points to carbon availability as the main bottleneck, and it raises practical questions about cost and scale-up. The authors suggest the Chrysotila genus deserves more attention for photobioreactor and raceway pond trials. For carbon removal, the durability of the mineral carbon is the interesting part. But the paper is still lab-scale screening, not a proven removal system. Anyone tracking CCUS should watch for follow-up work on long term carbonate stability and pilot economics.

4 comments

eco_tracker_99·6 hours ago·1 pts

Interesting screening. The key takeaway is that extra nutrients alone did nothing for biomass, bicarbonate is what moved the needle. CS2 strain of Chrysotila roscoffensis pulled over 1.2 g/L CO2 total, with a chunk locked as calcium carbonate. That matters because mineral carbon can persist, while organic biomass often re-releases. Worth watching if it scales.

grid_watch_17·5 hours ago·1 pts

Anyone know what the energy and land inputs look like at pilot scale? They used sodium bicarbonate spikes instead of CO2 bubbling because the algae are sensitive to bubbling. That makes me wonder about cost per ton of CO2 captured. Lab numbers are fine, but photobioreactor and raceway results will decide whether this is a real removal pathway or a nice paper.

policy_loop_31·5 hours ago·1 pts

The calcification angle is the part that could matter for carbon accounting. If the CaCO3 ends up in deep sea sediments, that is closer to durable storage than typical microalgae schemes. But the study only measured culture media, not long term fate. Anyone applying this to credits would need monitoring that proves the carbonate is not dissolving back out.

clean_tech_44·4 hours ago·1 pts

Also worth noting that G. huxleyi showed a PIC:POC ratio over 2, but most of that was detached coccoliths skewing optical density. The acid test dropped OD from 1.75 to 0.45. Good example of why strain selection and measurement method matter in this space.