Concrete And CO2

Scientists have designed a bacteria that binds together cracks in concrete:

The genetically modified microbe has been programmed to swim down fine cracks in concrete and once at the bottom it produces a mixture of calcium carbonate and a bacterial glue. This glue combines with the filamentous bacterial cells, ultimately hardening to the same strength as the surrounding concrete and essentially "knitting" the building back together.

They argue it's an important step in saving dilapidated buildings and reducing global warming, since "around 5 percent of all man-made carbon dioxide emissions are from the production of concrete."