By Asitha Jayawardena

Specially prepared bacteria could turn carbon dioxide (CO2) into fuel, plastic and useful chemicals, reveals a new study by Newcastle University. The research study raises the possibility of converting atmospheric CO2 to useful chemicals.

Carbon dioxide (CO2) is the most common greenhouse gas in the atmosphere and the rise of CO2 over 410ppm has caused the impacts of worsening climate change.

The CO2 research study

At Newcastle University, the researchers created a bioreactor full of Escherichia coli (E. coli) bacteria to capture CO2 using hydrogen gas (H2) to convert it into formic acid. In the reverse of this reaction, formic acid is formed from H2 and CO2 in the presence of an enzyme in E. coli. In nature, formic acid is a vinegar compound that ants used to ward off predators (Formic comes from the Latin ‘formica,” meaning ant.)

The reversal of the normal reaction in E. coli made the bacteria switch out molybdenum for tungsten. Molybdenum is a metal that is normally a critical part of the enzyme. The bacteria are grown in an excess of tungsten. “This is fairly easy to do as E. coli cannot readily tell the difference between the 2,” says the lead investigator Dr Frank Sargent of the School of Natural and Environmental Sciences, Newcastle University.

A special pressurized bioreactor filled with H2 and CO2 was used to make the gases available to the microbes. Under gas pressure, bacteria could grow and generate formic acid from CO2.

Dr Sargent developed the idea when he read about the emergence of life on earth. Three and a half billion years ago, a high level of CO2 and hydrogen was present in the atmosphere but not oxygen. Below 10,000 metres below the ocean surface, cellular life had begun to evolve. These compounds need to be turned into carbohydrates on which all life depends. That is what the researchers found in E. coli. 

Worldwide, societies understand the importance of combating climate change, developing sustainable energy sources and reducing waste, said Dr Sargent. Reducing carbon dioxide emissions will require a basket of different solutions and biology and microbiology offer some exciting options, he 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,” said Dr Sargent. “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.”

Carbon capture worldwide

“Carbon capture” technologies used around the world are to do with microbes that captures CO2. Some technologies capture CO2 directly from the air with a 97% efficiency.

At the Paul Scherrer Institute PSI and ETH Zurich, researchers explored different technologies to remove CO2 directly from the air. Absorbed from the atmosphere, CO2 is then either buried or used in carbon-based fuels. 

Such a technology would not remove the need to reduce carbon emissions but could work with other CO2 reduction plans so that the countries could achieve climate goals. 

More…

Bacteria ‘could turn CO2 into fuel, plastic or useful chemicals’, new study shows https://uk.yahoo.com/news/carbon-capture-co-2-155820363.html

Converting CO2 Into Useful Chemicals With Engineered E. Coli https://www.technologynetworks.com/immunology/news/converting-co2-into-useful-chemicals-with-engineered-e-coli-353579

Professor Frank Sargent, Newcastle University https://www.ncl.ac.uk/nes/people/profile/franksargent.html