It might not be long before we’re able to construct buildings with bacteria. Biology, rather than machining, is now emerging as a leading contender to assemble our future environment. Medicine and biofuels have tapped biology for mass production, but more robust materials for everyday life--roofs, beams, floor panels, car seats--are still the domain of factories. Now the ability to redirect and engineer biological processes and then capture this understanding in computational models, means that cells could soon become our factories.
Bacteria used to heal cracks in concrete: http://www.livescience.com/8960-designer-bacteria-heal-cracks-concrete-buildings.html