Biodesign is a quickly growing field that uses materials derived from living organisms rather than finite resources or synthetics. Living materials—made from anything that can reproduce, including plants, animals, insects, fungi, and even bacteria—have the potential to be more sustainable, healthier, and higher performing building alternatives than traditional materials. Biologists, engineers, and designers are coming together to develop bio-based products of all kinds, from structural materials and natural insulations to packaging, fibers, and leathers.
This could mean fabricating textiles from the byproducts of orange juice (mostly pulp and skin), making insulation from straw, or even using bacteria to grow cement. Really, anything that can reproduce has the potential to become a biomaterial. Some believe that these technologies could replace synthetic materials made through fossil fuels. Many biological materials are free of the toxic additives and byproducts found in traditional synthetic materials like insulation, PVC, and concrete. And without synthetic ingredients, many of these materials can biodegrade or be composted safely at the end of their life cycle rather than being sent to landfills. That’s why biomaterials can be much better suited to a circular economy, which is underpinned by a transition to renewable materials that don’t expend much energy to produce, reduce environmental impacts, and eliminate waste.
Clarifying Nuanced Terminology
However, not all biomaterials are made from 100 percent natural ingredients, and they’re not all necessarily sustainable, biodegradable, healthy, or nontoxic. There are different bio-terminologies for materials produced using different criteria, and it’s important to understand the difference in order to make fully informed decisions. A material might be biofabricated, biosynthetic, or biobased. We’ll explain each in order of specificity.
The umbrella term under which the rest fall is “biomaterial.” It’s the least specific term – biomaterials may have bio content ranging anywhere from less than 10 percent to 100 percent. Next is “biobased.” Biobased materials, according to the European Committee for Standardization, are “wholly or partly derived from biomass, such as plants, trees or animals (the biomass can have undergone physical, chemical or biological treatment).” For example, conventional leather is a biobased material that often undergoes chemical treatments and synthetic dying processes. Next in specificity is “biofabricated,” which describes materials that were produced by living organisms. Rather than plants or animals, these are microorganisms such as bacteria, yeast, or fungi – like mycelium (the underground root structure of mushrooms) that grows cellulose leather alternatives. All biofabricated ingredients need further processing to produce the final material structure. And finally, “biosynthetic” materials are made in whole or in part, of bio-derived compounds. These compounds can be made either with a biological material, and/or using a process performed by a living microorganism. For example, microorganisms ferment sugars or other substances, which in turn create precursor chemicals for synthetic polymers such as polyesters or polyurethanes.
The takeaway from hashing out all of these terms is that not all biomaterials are the same. We can’t assume that biomaterials are always better than other materials, or that they’ll decompose if you put them into the ground. It’s always important to understand how these materials were made, what other ingredients or processing were involved, and what their impacts are. A considerate, detailed evaluation of each product can mean the difference between a flashy trend and a meaningful, sustainable strategy that encourages a true shift in the industry.
Next, we’ll explore just a few of the exciting biomaterial innovations in the building industry.
Concrete and Bricks
Concrete is responsible for more greenhouse gas emissions than any other material. That’s why several companies have developed biofabricated concrete alternatives using bacteria. Rather than the traditional curing and hardening process, some of these companies have eliminated the need for firing or baking by taking advantage of bacteria that harden concrete at room temperature. One of these companies, bioMASON, feeds units mixed with microorganisms an aqueous solution and the bricks harden in less than 72 hours. Other companies have developed regenerative concrete, which “self-heals” any cracks when activated by water. (This involves keeping the bacteria that builds the concrete alive to make more when needed.)
Biobricks have also gained visibility in the last decade. In 2014, architect David Benjamin designed Hy-fi, an organic brick structure made from fungi and farm waste, that was installed in MoMA’s PS1. Once the structure was removed, it was composted.
These days, insulation can be made out of nearly anything, from seaweed and straw to wool and hemp. Seaweed insulation is made using heat and high-pressure compression on seaweed mats. Pressed straw panels draw on not only nature’s solutions, but also the way that indigenous peoples have been constructing over thousands of years. Combined with modern technology, straw becomes a high performing, energy efficient insulation material. Hempcrete too, a bio-composite material made of the inner core of the hemp plant, is great for insulation, and it doesn’t require fungicides or pesticides. Even denim and cotton prove to be effective insulation, meeting the highest ASTM testing requirements for fire and smoke ratings, fungi resistance, and corrosiveness.
Textiles too are an area of significant biomaterial innovation. Recent developments include bioleather made from collagen, the same protein used in animal leather, which is created using DNA-sequence editing to form a network of fibers. Under carefully controlled conditions, mycelium can also produce a material that when cured and tanned, is pretty similar to leather. It’s flexible, durable, and an extra plus—water resistant. Other manufacturers have biofabricated a silk product by developing proteins like those found in spider DNA and putting them in yeast. During fermentation, the yeast produces silk protein, which can then be spun into fiber.
And in the world of biomaterials, there’s so much more. There are wall panels made with pressed flower petals, plants, moss, lavender and hay. There’s wheatboard—a wood alternative made from reclaimed sorghum straw. Floor tiles made from mycelium composite and bio-based resin, leathers made of pineapples and cacti! The role of designers can’t be understated—both in the development of these materials, and in their specification. These materials haven’t been scaled enough to make a significant impact on the building and design industries, but they certainly may in the years to come.