The rise in greenhouse gases and the resulting climate crisis is prompting scientists to think outside the box when it comes to sequestering carbon dioxide. Researchers have created a paint containing living cyanobacteria that produce oxygen and capture carbon dioxide and are also resistant to extreme environments, meaning the new paint could be used in a range of areas including outer space.
We have already seen cyanobacteria, or blue-green algae, being proposed as building blocks for new green materials due to their photosynthetic properties.
Cyanobacteria fix carbon dioxide through photosynthesis and convert it into organic compounds. They can photosynthesize efficiently even in harsh environments. Additionally, they grow rapidly and in most cases can be genetically modified.
Researchers at the University of Surrey in the UK have developed a water-based paint that produces oxygen and absorbs carbon dioxide, containing a type of cyanobacteria, which they call 'green living paint'.
Suzie Hingley-Wilson, corresponding author of the study, said: "With the increase in greenhouse gases in the atmosphere, especially carbon dioxide, 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 coatings') can help meet these challenges by reducing water consumption in the often water-intensive bioreactor process."
The researchers set out to immobilize metabolically active cyanobacteria in a porous but mechanically stiff coating, allowing them to fix carbon and produce oxygen. They compared three types of cyanobacteria and found that Chroococcidiopsiscubana performed best. C. cubana is an "extremophile" strain, meaning it can withstand extremes of temperature and pH, high concentrations of salt, arid environments and radiation.
The research process is relatively simple. The researchers immobilized the cyanobacteria in a biocoating made of polymer particles in water, which was then completely dried and rehydrated. They found that compared to other species used, Chroococcidiopsis remained viable and its oxygen production steadily increased, peaking at 0.4 grams of oxygen per gram of biomass per day. A month of continuous measurements of dissolved oxygen showed no sign of a decrease in its activity. They estimated the carbon capture to be 0.31 grams of carbon dioxide per gram of biomass per day.
The researchers say their results suggest that extremophilic cyanobacteria are ideal candidates for biocoatings and other biotechnologies, including in outer space.
Simone Krings, first author of the study, said: "Photosynthetic cyanobacteria have an extraordinary ability to survive in extreme environments, such as drought and high levels of ultraviolet radiation. This makes them potential candidates for colonization of Mars."
Future research will focus on optimizing the use of this cyanobacterial strain as a biocoating.
The research was published in the journal Microbiology Spectrum.