An innovative paint that contains oxygen-producing bacteria capable of capturing carbon dioxide (CO₂) has been created by scientists from the University of Surrey. Researchers suggest this paint, known as "biocoating," could be used in extreme environments, such as space stations.

Biocoatings are a type of water-based paint that encase live bacteria within layers. Besides capturing carbon, they can also serve as bioreactors or as biosensors. Surrey's creation, named “Green Living Paint,” features Chroococcidiopsis cubana, a bacterium that undergoes photosynthesis to produce oxygen while capturing CO₂. This species is usually found in the desert and requires little water for survival. Classified as an extremophile, it can survive these extreme conditions.

Dr. Suzie Hingley-Wilson, a senior lecturer in Bacteriology at the University of Surrey said: "With the increase in greenhouse gases, particularly CO₂, in the atmosphere and concerns about water shortages due to rising global temperatures, we need innovative, environmentally friendly, and sustainable materials. Mechanically robust, ready-to-use biocoatings, or 'living paints,' could help meet these challenges by reducing water consumption in typically water-intensive bioreactor-based processes." 

To investigate the suitability of C. cubana as a biocoating, researchers immobilized the bacteria in a mechanically robust biocoating made from polymer particles and natural clay nanotubes in water, which was fully dried before rehydrating. They observed that the bacteria within the biocoating produced up to 0.4 g of oxygen per gram of biomass per day and captured CO₂. Continuous measurements of oxygen showed no signs of decreasing activity over a month.

In contrast, researchers conducted similar experiments with the bacterium Synechocystis sp., another cyanobacterium usually found in freshwater. Unlike its desert counterpart, it was unable to produce oxygen within the biocoating.

Simone Krings, the lead author and a former Postgraduate Researcher in the Department of Microbial Sciences at the University of Surrey, said: "The photosynthetic Chroococcidiopsis have an extraordinary ability to survive in extreme environments, like droughts and after high levels of UV radiation exposure. This makes them potential candidates for Mars colonization." 

Professor Joseph Keddie, professor of soft matter physics in the School of Mathematics and Physics at the University of Surrey, said: "Our research grant from the Leverhulme Trust enabled this interdisciplinary project. We envision our biocoatings contributing to a more sustainable future, aligning perfectly with the vision of our Institute for Sustainability, where both Dr. Hingley-Wilson and I are fellows."

- This press release was originally published on the University of Surrey website