So I’m going to stick with a theme here and try to talk about beneficial uses of microbes in the built environment (like stabilizing the ground underneath buildings to mitigate the effects of earthquakes).
Today I came across the research from a group of students at Newcastle University who designed a strain of Bacillus that they call “BacillaFilla”. Basically it would release calcium carbonate and some sort of binding compound and form concrete. Theoretically this could be used for both building repair and maintenance if it scales up to a real-world setting (they still have to engineer the bacteria first). Considering the expense and environmental impact of making concrete, extending the lives of existing structures would have a big impact.
As a side note, this was the winning entry in the 2010 International Genetically Engineered Machines (iGEM) competition.