Are photosynthetic bricks the green building material of the future?

Blue-green algae brick University of Colorado Boulder College of Engineering and Applied Science

Imagine a building material composed primarily of sand, gelatin, and bacteria that has the benefits of concrete but without its carbon footprint. A group of researchers at the University of Colorado Boulder have done exactly that

“We wanted to blur the boundaries between nature and the built environment by bringing building materials to life,” says Wil V. Srubar III, assistant professor in the Civil, Environmental and Architectural Engineering department at the school. 

While it sounds a bit sci-fi, it’s an innovation–dubbed living building materials (LBMs)–that has those in the industry excited.

This new material works by incorporating cyanobacteria, which captures energy through photosynthesis and therefore absorbs carbon dioxide. The cyanobacteria (yes, that’s the blue-green algae so loathed by lakeside dwellers for its toxicity and smell) also gives the bricks a green color, which fades as it dries, and also remains ‘alive’, meaning it can be used to generate more bricks.  

You’re not alone if this is making you a bit uneasy but fear not, says Professor Srubar. “The bacteria are, in effect, encapsulated–and dormant–inside the bricks rendering it extremely unlikely to cause harmful health issues, especially while in service,” he says. It is put into use under “precise triggers of temperature and humidity” in order to grow the materials, making it highly unlikely that there would be any sort of spontaneous growth.

What’s more, he notes that there are certain to be regulations surrounding this process as it moves closer to real-world applications. In other words, he’s confident that your cyanobacteria-infused cottage construction won’t ooze its way into your lake and wreak havoc. “While cyanobacteria are in the same family, algae itself is not necessarily the cause of the havoc,” he says. “The algae is really innocuous, like the algae in your fish tank.” It isn’t the algae that’s the problem with algal blooms necessarily, it’s the overabundance of nitrogen and phosphorus which create the conditions for the algae to bloom.  

While still in the development phase, Professor Srubar believes these bio-bricks herald the future and expects them, or a similar version, to be commercially available within the next five to 10 years.

It’s a welcome alternative to carbon-intensive concrete, which is the second most consumed material on earth (water is number one) and emits annually more carbon than the top two countries, U.S. and China. “We envision this material could be used as a building block for…carbon-sequestering mortar, lightweight concrete, biologically active surfaces, temporary disaster-relief shelters or roadways.” It could be designed to indicate the presence of toxic materials or light up to reveal structural damage. 

It’s also an attractive option in environments where it’s difficult or impossible to bring in materials. The advantage of LBMs is that they require only fairly common materials and then, essentially, grow themselves. 

One of the potential benefits of this is that materials wouldn’t have to be taken to other places (planets!), rather bricks could be grown there. “We believe this material is particularly suitable in resource-scarce environments, such as deserts or the Arctic—even human settlements on other planets. Again, the sky is the limit, really, for creative applications of the technology.” Looking to cottage on Jupiter? Line up your LBM contractor now.

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