Images courtesy of Perkins+Will

Living Architecture: Growing Buildings from Bacteria

A research project at the University of Colorado Boulder is paving the way for self-healing, air-cleaning buildings made from living bacteria. Lucy Ingham finds out more

According to the World Green Building Council, the construction industry is responsible for 11% of the world’s carbon emissions, much of which comes from concrete. There is now a concerted effort underway to use alternatives, with wood among the leading choices. But what if there was an alternative to concrete that not only offered dramatic environmental improvements, but also healed itself and scrubbed the air of toxins?

This may be some way off being a viable option for architects specifying construction materials, but that doesn’t mean it isn’t on its way. In January, researchers from the University of Colorado Boulder published a paper in the journal Matter that detailed such a material, and it could ultimately revolutionise the built environment.

The material in question is made from a cyanobacteria, which can absorb carbon dioxide gas to make calcium carbonate. The researchers have developed a method to create living bricks from the bacteria by feeding it sand and gelatin.

These are not only durable, but can self-heal, even growing to form new bricks if they are cut in half.

“We already use biological materials in our buildings, like wood, but those materials are no longer alive,” said Wil Srubar, an assistant professor in the Department of Civil, Environmental and Architectural Engineering (CEAE).

“We're asking: why can't we keep them alive and have that biology do something beneficial, too?”

The ‘Revolution: Changing the Office Paradigm’ project is Perkins and Wills’ proposal for an office building that is resilient and flexible by design.

A living, self-healing building material

There are clear environmental benefits to such a material, as the bacteria removes carbon dioxide from the air rather than contributing to its presence.

Furthermore, while the resulting material currently only works in certain humidity conditions, where it does function it has durability comparable to mortar.

“You can step on it, and it won't break,” said Srubar.

Moreover, it has far better bacteria survival rates than self-healing concretes that are being developed, where just 1% of the bacteria survives past 30 days. With this material, the rate is between 9-14%.

“ What we're really excited about is that this challenges the conventional ways in which we manufacture structural building materials. 

Perhaps most excitingly, it would have a profound impact on construction, as it could make it possible to grow entire structures from sacks of the base ingredients on site, at a rate very different from other methods such as 3D printing.

“What we're really excited about is that this challenges the conventional ways in which we manufacture structural building materials,” said Srubar.

“We know that bacteria grow at an exponential rate. That's different than how we, say, 3D-print a block or cast a brick. If we can grow our materials biologically, then we can manufacture at an exponential scale.”

Making bacteria buildings work for the world

The material is, of course, at the very early stages of development, but the potential is significant.

“This is a material platform that sets the stage for brand new exciting materials that can be engineered to interact and respond to their environments,” said Srubar.

“We are just trying to bring building materials to life, and I think that is the nugget in this whole thing. We're just scratching the surface and laying the foundation of a new discipline. The sky is the limit.”

“ We're just scratching the surface and laying the foundation of a new discipline. The sky is the limit. 

One of the biggest challenges Is making it work in lower humidity environments, but the researchers also plan to add the ability to sense and respond to toxins in the air.

It could even ultimately prove to be a viable option for off-Earth construction.

“In austere environments, these materials would perform especially well because they use light from the sun to grow and proliferate with very little exogenous material needed for their growth," said Srubar. "

“It's going to happen one way or another, and we're not going to be trucking bags of cement all the way to Mars. I really do think that we'll be bringing biology with us once we go.”

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Images courtesy of the College of Engineering and Applied Science at the University of Colorado Boulder