Specially prepared bacteria could be used to turn carbon dioxide (CO2), the most common greenhouse gas, into chemicals, plastic or even fuel, a new study has shown.
The research raises the possibility of turning CO2 in the atmosphere into useful chemicals.
Researchers from Newcastle University created a bioreactor full of E coli bacteria to capture CO2 and turn it into useful chemicals.
The breakthrough is based on reversing a chemical reaction catalysed by bacteria, by growing the bacteria with a supply of molybdenum.
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The new reaction captures CO2, turning it into formic acid, a vinegar compound ants use to ward off predators.
Lead investigator Frank Sargent of the School of Natural and Environmental Sciences, Newcastle University, said: "The ultimate aim would be to capture wasted CO2 using renewable hydrogen gas from biohydrogen – as in this research – or electrolysis powered by renewable electricity, and convert it to formic acid.
"Then we can make fuel, plastic or chemicals. This is the vision of a truly cyclic bioeconomy where CO2 is constantly produced, captured and returned to the market."
Sargent said: "Around the world, societies understand the importance of combating climate change, developing sustainable energy sources and reducing waste. Reducing carbon dioxide emissions will require a basket of different solutions. Biology and microbiology offer some exciting options."
The investigators used a special pressurized bioreactor filled with H2 and CO2 to make the gases available to the microbes.
Sargent said: "It worked—the bacteria could grow under gas pressure and generate formic acid from the CO2.”
He developed the idea from reading about the emergence of life on Earth.
Three and a half billion years ago, there was no oxygen in the atmosphere, but there were high levels of CO2 and hydrogen, and cellular life had begun evolving 10,000 metres below the ocean’s surface.
Back then, these compounds would have needed to be converted into the carbohydrates on which all life depends.
That could have been accomplished by an enzyme "such as the one we found in E coli, hydrogenating carbon dioxide into an organic acid," said Dr. Sargent. "We wanted to try this in the lab."
Using microbes to capture CO2 is one of several "carbon capture" technologies, which are currently being trialled around the world.
Some of these technologies can capture CO2 directly from the air with up to 97% efficiency, a study found earlier this year.
Researchers at the Paul Scherrer Institute PSI and ETH Zurich investigated different technologies to remove CO2 directly from the air.
CO2 is absorbed from the atmosphere and then either buried or used in carbon-based fuels.
The researchers cautioned that such technology won’t remove the need to cut carbon emissions, but could work alongside carbon reduction to help countries hit their climate goals.
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