In 2021 alone, 2.9 billion tons of CO2 were emitted by the cement production industry, corresponding to more than 7% of total global CO2 emissions. The emissions occur when the cement is heated, as the high temperatures cause CO2 release.
Now, using unique technology and inspiration from corals, researchers are working on solving the problem.
“Other biologists typically try to design bacteria that mimic photosynthesis, in which plants capture CO2 from the air and convert it into sugar. The problem is that this is very difficult to do. That’s why we chose to say, forget about plants. We want to mimic corals,'” says Professor Ivan Mijakovic, who is head of the group and came up with the original idea for the project.
By transferring genes from microorganisms to a particularly tough kind of bacteria, the team has already succeeded in getting the bacteria to produce an enzyme that can quickly and efficiently bind CO2 to limestone, or calcium carbonate, which is one of the main ingredients in cement. The goal is for cement factories to have a bioreactor with the specially designed bacteria, also called a cell factory, to ensure that the CO2 emitted is captured rather than leaking into the atmosphere.
“It will work a bit like a green circle: The factory releases CO2 during heating, we capture it in the bioreactor, which binds the CO2 to calcium carbonate, the factory then reheats the calcium carbonate to make new cement, and once again we capture the CO2 released,” said Ph.D. student Chenxi Zhang.
Postdoc Colleen Varaidzo Manyumwa who is also involved in the research explained, “Innovation is always challenging, and some days are definitely easier than others. But I believe that within a few years, this solution will exist as one of several solutions to remove CO2 from the atmosphere and help slow down climate change,” she says.
Image: Bacteria designed by researchers can help solving one of the big CO2 challenges in the construction industry. Credit: Thomas Steen Sørensen