BacillaFilla to the Rescue! (only if you’re concrete, though)

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Installing rebar in a concrete floor during a ...
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Researchers have designed bacteria that can produce a special glue to knit together cracks in concrete structures. The students from the University of Newcastle were competing for the International Genetically Engineered Machine competition, run at MIT. (This year some 130 student teams competed.) The product employs a microbial strain of Bacillus subtilis. The particular genetically modified strain does not survive in the wild, so proliferation will be difficult (and you will have to buy it to use it 🙂 ).

About 12 billion tons of concrete are used annually. And, that concrete needs maintenance and replacement. According to the Federal Highway Administration, of our 1.5 billion km of roads, some 260,000 km is already in need of repaving (about 17%). This is separate and above our 5 million km of local roads that have been allowed to decay. [One should also note that concrete produces carbon dioxide as its “sets”, which enters the atmosphere.]
One has to recognize that while we think of concrete as a solid mass, it really is a porous structure (comprised of water and cement) akin to very small balls packed together, with voids between the balls. (Think of a dry sponge.) When it rains (or snows) water slips into the voids (pores); when water freezes (in the winter), it expands in size and breaks apart the ‘sponge’ Adding salt to the roads makes the situation worse, since that decays the reinforcement bars (rebar) that are used to provide more structure and strength to our roads.
Team Newcastle (self-moniker), under the direction of Drs. Jennifer Hallinan and Neil Wipat, found that the bacterial spores (which they call “BacillaFilla” germinate upon contact with concrete and the pH of the milieu and enter the new cracks. As is true of many biofilms, the cells differentiate into different types. One produces of calcium carbonate crystals, another produces a polysaccharide (a bacterial glue), and others become filamentous. This biofilm then hardens to about the same strength as the original pour, filling the new voids (from the cracks) and “knits” the components back together.

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