Microbe Designed to Heal Concrete
BacillaFilla bacteria developed to heal concrete. Photo by Newcastle University.
Reducing the embodied energy of materials is a strategy that has received serious attention recently, resulting in a few extreme examples of materials that are “grown” rather than manufactured—thus virtually eliminating the energy that would typically be used in processing. While material production is a critical point of potential energy savings, architects know that long-term maintenance can result in even greater energy consumption over a material’s life cycle. So, why not “grow” materials in this capacity as well?
A team of Newcastle University students has recently unveiled a proposal for a self-healing concrete powered by bacteria. Led by instructor Jennifer Hallinan, the students developed a genetically modified microbe designed to reconstruct cracks that form in concrete. When a fissure forms in the material, the bacteria swim to the bottom of the crack and create a mixture of calcium carbonate and microbial glue that effectively patches the concrete. This bacterial patch ultimately “cures” to the same strength as the surrounding material.
According to Hallinan, “Around five per cent of all man-made carbon dioxide emissions are from the production of concrete, making it a significant contributor to global warming. Finding a way of prolonging the lifespan of existing structures means we could reduce this environmental impact and work towards a more sustainable solution. This could be particularly useful in earthquake zones where hundreds of buildings have to be flattened because there is currently no easy way of repairing the cracks and making them structurally sound.”
The multidisciplinary student team recently won a gold medal for their “BacillaFilla” microbe in the International Genetically Engineered Machines contest (iGEM) competition sponsored by MIT. The energy-saving potential of the students’ surprising invention suggests that we will see similar biologically-driven strategies toward maintaining building materials in the future.