In addition to turning into starch, what else can carbon dioxide turn into? It turns out to be rocks!

Popular Science Times (Intern Wang Yuke) Microorganisms that can quickly convert carbon dioxide into rocks can seal the greenhouse gas in storage sites deep underground, such as depleted oil or natural gas reservoirs.

American environmental journalist James Deen published a paper in the latest issue of the international scientific journal "New Scientist" stating that bacteria may accelerate the mineralization of carbon dioxide under extreme conditions, and injecting this microorganism into the ground together with the captured carbon dioxide can store greenhouse gases more durably.

Researchers at the South Dakota School of Mines and Technology's School of Geological Engineering isolated Pasteurella, known to be able to withstand high temperatures and pressures, from compost in Washington state. In laboratory tests, the researchers compared the mineralization rate of carbon dioxide dissolved in water with and without these microorganisms. They tested the process under different conditions of temperature, pressure and salinity. These conditions are comparable to the extreme conditions deep underground where carbon dioxide may be stored.
In the absence of microorganisms, the researchers did not observe any CO2 mineralization.

At 80°C and a pressure about 500 times that at sea level, in the presence of microorganisms, carbon dioxide forms mineral crystals in just 10 days. The key to this rapid mineralization is that bacteria reproduce an enzyme. The carbon dioxide solution dissolves the rock, and the enzyme quickly reduces the acidity of the solution, so that the magnesium and calcium released from the rock can form carbonate minerals.

Microbes living on the surface often make the enzyme, said Brett Lingwall of the South Dakota School of Mines and Technology. Humans also make the enzyme, but they don't usually survive long in extreme conditions.

The researchers also plan to test Bacillus isolated from deep within an old mine in South Dakota, as well as genetically modified strains, to see which microbe performs best.