Living building materials with bacteria

University of Colorado Boulder researchers have developed a new approach to designing more sustainable buildings with help from some of the tiniest contractors out there.

Such structures could, one day, heal their own cracks, suck up dangerous toxins from the air or even glow on command, based on experiments with cyanobacteria belonging to the genus Synechococcus. Under the right conditions, these green microbes absorb carbon dioxide gas to help them grow and make calcium carbonate -- the main ingredient in limestone and, it turns out, cement.

To begin the manufacturing process, the researchers inoculate colonies of cyanobacteria into a solution of sand and gelatin. With the right tweaks, the calcium carbonate churned out by the microbes mineralize the gelatin which binds together the sand -- and, which can then produce a brick.

Such bricks would actually remove carbon dioxide from the air, not pump it back out. In the new study, the team discovered that under a range of humidity conditions, they have about the same strength as the mortar used by contractors today.

The researchers also discovered that they could make their material reproduce. Chop one of these bricks in half, and each of half is capable of growing into a new brick. Those new bricks are resilient: According to the group's calculations, roughly 9-14% of the bacterial colonies in their materials were still alive after 30 days and three different generations in brick form. Bacteria added to concrete to develop self-healing materials, in contrast, tend to have survival rates of less than 1%.

See:

Chelsea M. Heveran, Sarah L. Williams, Jishen Qiu, Juliana Artier, Mija H. Hubler, Sherri M. Cook, Jeffrey C. Cameron, Wil V. Srubar. Biomineralization and Successive Regeneration of Engineered Living Building Materials. Matter, 2020; DOI: 10.1016/j.matt.2019.11.016

 Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)