A type of bacteria-based living concrete could one day help reduce the environmental impact of the construction industry.
Wil Srubar The University of Colorado and his colleagues used a type of bacterium, Synechococcus, to create building blocks of living concrete in different shapes.
The team combined the bacteria with gelatin, sand and nutrients in a liquid mixture, then introduced it into a pre-formed mold. With heat and sunlight, the bacteria produced calcium carbonate crystals around the sand particles, in a process similar to that which leads to the formation of shells in the ocean.
Once cooled, the gelatin solidified the mixture into a gelatinous form. Once this gel has been dehydrated (a process that lasted several hours), the material has reached the hardness necessary for use in construction.
The team compared the living material to concrete and concrete. It is a mixture of gravel, sand and concrete combined with water. But its mechanical properties are more similar to mortar, a weaker material usually made with cement and sand. It does not yet have the strength of normal bricks, but they are working on it.
The advantage of living cement? It multiplies by itself
An advantage of using bacteria to create cement is that if they are not completely dehydrated, they continue to grow. One brick can be split to make two, just add sand and nutrient solution. The team demonstrated that a living brick can 'reproduce' to eight bricks after several divisions.
"If we refine the process and use species of bacteria that grow at higher rates, we can theoretically move from a linear production approach to an exponential production approach", he claims Šrubař.
The process can make cement production more environmentally sustainable, which would otherwise be environmentally wasteful. Cement is the second most consumed material on earth after water. For this this research, and others on the biocemento, they are really important.
The work was funded by DARPA (United States Defense Advanced Research Projects Agency) and Srubar says the team is now in talks with the U.S. Department of Defense to increase production of this biomaterial and pilot its production. use in construction.
Research reference: Matter, 10.1016 / j.matt.2019.11.016