New 'Living' Material That Sucks CO2 From Air Developed By Scientists

Scientists have developed a new 'photosynthetic' material capable of absorbing carbon dioxide (CO2) that can one day be used in buildings to fight climate change. The Swiss researchers have created the innovative substance using blue-green algae (cyanobacteria), which converts CO2, sunlight and water into oxygen and sugars through photosynthesis.

Under specific nutrient conditions, it can also turn CO2 into sturdy, eco-friendly construction components and solid minerals such as limestone, providing permanent carbon storage while strengthening the material.

"Cyanobacteria are among the oldest life forms in the world. They are highly efficient at photosynthesis and can utilise even the weakest light to produce biomass from CO2 and water," said Yifan Cui, one of the two lead authors of the study.

The carrier material that harbours the living cells is a hydrogel - a gel made of cross-linked polymers with a high water content, according to the study published in the journal Nature Communications.

To ensure that the cyanobacteria live as long as possible and remain efficient, the researchers optimised the geometry of the structures using 3D printing processes to increase the surface area, increase light penetration and promote the flow of nutrients.

"We engineered printable photosynthetic living materials that were capable of carbon sequestration through biomass accumulation and inorganic carbonate precipitation," the study highlighted.

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Test results

Test results showed that the material continuously absorbed CO2 over a 400-day period, with most of the "sequestered carbon stored in the stable mineral form".

The total amount of CO2 sequestered through mineral formation after 400 days was 26 milligrams per gram of CO2 per gram of material. This is significantly more than many biological approaches and comparable to the chemical mineralisation of recycled concrete (around 7 mg CO2 per gram).

"With minimum requirements of sunlight and atmospheric CO2, our photosynthetic living materials showed a consistent carbon sequestration efficiency throughout the entire incubation period," the researchers stated.

At an art exhibition in Venice, Italy, the researchers presented the material in the form of two tree trunk-like objects that could absorb up to 18 kilograms of CO2 per year or as much as a 20-year-old pine tree.