Capture process turns CO2 into construction materials

An MIT engineer is developing a process that would not only remove carbon dioxide from the environment, but also turn it into solid carbonates that could be used in construction.

’We want to capture carbon dioxide and turn it into something that will be stable for hundreds of thousands of years rather than store it underground,’ said Angela Belcher, the WM Keck professor of energy at the university.

By genetically engineering ordinary baker’s yeast, Belcher and two of her graduate students, Roberto Barbero and Elizabeth Wood, have created a process that can produce about two pounds of carbonate for every pound of carbon dioxide captured.

To create the yeast-powered process, Belcher drew inspiration from marine animals that build their own rock-solid shells from carbon dioxide and mineral ions dissolved in seawater.

Funded by the Italian energy company Eni, the new process requires two steps. The first step is capturing carbon dioxide in water. Second, the dissolved carbon dioxide is combined with mineral ions to form solid carbonates.

Since yeast does not normally perform any of those reactions, Belcher and her students had to engineer them to express genes found in organisms such as the abalone. Those genes code for enzymes and other proteins that help move carbon dioxide through the mineralisation process.

’We’re trying to mimic natural biological processes,’ said Belcher. ’But we don’t necessarily want to make the exact same structure that an abalone does.’

Some companies have commercialised processes that capture carbon dioxide and convert it to solid material, but those efforts rely on a chemical process to capture carbon dioxide. The MIT team’s biological system captures carbon dioxide at a higher rate, said Barbero. Another advantage of the biological system is that it requires no heating or cooling and no toxic chemicals.

Next, the team plans to try scaling up the process to handle the huge volumes of carbon dioxide produced at fossil-fuel-burning power plants.