BacillaFilla germs repair cracked concrete

United Kingdom – A group of engineering, micro-biology and bio-engineering students from Newcastle University have developed a genetically-modified microbe programmed to repair cracks in the concrete. Once at the bottom, it produces a mixture of calcium carbonate and a bacterial glue which combine with the filamentous bacterial cells to “knit” a building back together. Ultimately hardening to the same strength as the surrounding concrete, the aptly named “BacillaFilla”has been developed to prolong the life of structures which are environmentally costly to build.

“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,” explained joint project instructor, Dr Jennifer Hallinan. “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.”

As part of the research, the students have not only considered the advantages of their engineered bacteria, but also the potential risks to the environment. The BacillaFilla spores only start germinating when they make contact with the very specific pH of concrete. Once the cells have germinated, they swarm down the fine cracks in the concrete and are able to sense when they reach the bottom because of the clumping of the bacteria.

This clumping activates concrete repair, with the cells differentiating into three types: cells which produce calcium carbonate crystals, cells which become filamentous acting as reinforcing fibres and cells which produce a Levans glue which acts as a binding agent and fills the gap.

The nine students, whose backgrounds range from computer science, civil engineering and bioinformatics to microbiology and biochemistry, took part in the International Genetically Engineered Machines contest (iGEM), is run out of the Massachusetts Institute of Technology (MIT) in Cambridge, Boston. The aim is to get together a team of students from a variety of backgrounds to design and genetically engineer a bacterium to do something novel and useful.

Over 130 teams took part in this yearas event and it is the third time Newcastle University has won Gold. The team instructors were Professor Neil Wipat and Dr Jennifer Hallinan, and the advisors were Dr Wendy Smith, Dr Matthew Pocock, Dr Colin Davies, Dr Jem Stach and Professor Colin Harwood.
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