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Living in a home made from fungi and bacteria may sound like science fiction, but new research shows that researchers are one step closer to ultimately making it a reality.
A Montana research team grew a densely packed sponge entanglement of mycelium, a root system structure that connects fungal networks underground.
The ability to create durable load-bearing structures from living materials is still years away. However, the discovery is a key step in creating a sustainable alternative to cement, a binder for concrete, says Chelsea Heveran, a senior author of the study, published in the April 16 journal Cell Reports Physical Science.
According to Chatham House, a London-based think tank, over 4 billion tons of metric tons (4.4 billion tons) of cement are produced every year, contributing about 8% of the world’s carbon footprint. This means that if cement production is a country, it will rank third after China and the US based on its 2023 emissions.
“What would happen if we could do that in a different way using biology?” “We are a great source of energy,” said Heberan, an assistant professor of mechanical and industrial engineering at Montana State University Bozeman.
The study authors introduced bacteria that could produce calcium carbonate – fungi, the same compounds found in corals, eggshells and limestones, were introduced into fungal mycelium, which served as scaffolds. Through a process called biomineralization, calcium carbonate hardens the hard, soft mycelium into a hard, bone-like structure.
“We’re not the first to biologicalize anything and call it building materials. But if we wanted (bacteria) to live longer and do more together with them, we had some challenges to increase their survival rate,” Heberan said. “So, it’s why it gave us a scaffolding for fungal mycelium because it’s really robust and essentially biomineralised (itself).”
The team found that by naturally biologicalizing a fungus called Neurospora Crassa, killing it and then adding microorganisms, it helps to achieve harder materials in less time. Bacteria, called Pasteurii, which created a crystalline network of calcium carbonate around the fungal mycosis after metabolizing urea, It’s like bacterial food.
While other biomineized building materials are considered “living” for a few days only, Heberan said her team is able to keep the microbes active for at least four weeks, and that period could eventually be extended to months or years.
“We’re really excited to ask the next job: ‘Can we seal the cracks in the material?’ Or “Can you feel something using these bacteria?” For example, imagine that the air quality in your building is poor, and can these bricks be illuminated by your walls? “Heberan said. “We couldn’t do that because before, microorganisms were not fully alive, but now they’re very alive.”
More testing is needed to find living building materials to replace cement before they are used in homes, fences or other construction, said Avinash Manjula-Basavanna, a bioengineer who was not involved in the study.
“These types of experiments are being conducted on a small scale. … They do not necessarily reflect the properties of bulk materials,” says Mandurah Basavanna, a senior research scientist at Northeastern University in Boston. “It’s not rigidity that people are interested in when it comes to construction materials. It’s strength, the ability to carry the load ().”
Although the strength and durability of living building materials is not yet comparable to concrete, Heberan said mycelium remains a promising base. Thanks to its flexibility, the adhesive material can be shaped to include vessel-like channels in beams, bricks and walls.
Just like blood vessels in the human body, cells within living building materials need structures that can supply nutrients to stay alive. However, adding these structures to the design of building materials could weaken them and present challenges for future research, Manjula-Basavanna said.
“In the future, I think they could be useful for these small structures, single-storey buildings. That’s very feasible,” Mandurah Basavanna said. “Maybe five to ten years from now.”
Fungi are also a potential danger of respiratory dyspnoea, and killing mycelium reduces the ability to produce allergens, but more research needs to be done before it is considered safe to live there, Heberan said.
“It’s very clear to conceptualize a test framework where the material needs to be strong enough because these types of standards already exist,” Heberan said. “However, there is no regulatory standard for bricks that contain cells.”
It’s safe to say that the fungal bricks sold at your local home improvement store are not available at any time.
Heveran’s team is just one of many in the country examining the potential of mycelium. This is used for other soft items such as packaging and insulation.
Heberan said several government agencies are interested in the potential use of already living building materials.
“There are a lot of ‘ifs’ to benefit from the costs from now on for the average household,” Heberan said.
“But for society, if you’re trying to build infrastructure for the community that really needs it, or if you’re trying to build infrastructure in space, this may be much easier than cartting cement or concrete,” she explained. “The possibilities are really exciting for me.”