Anyone who has spent even a small amount of time outdoors is likely to have noticed that, for all its randomness and chaos, the natural world actually contains quite a bit of order. Explore the shallows along a beach and you’ll find the elegant, logarithmic spirals that make up sea shells. Wander through a forest and the hypnotic patterns woven into spiderwebs will beguile you and the insects that fly into them. Even the simplest plant and tree leaves contain impressively intricate vascular networks to move nutrients around.
Society has long drawn inspiration from such arrangements. Biomimicry, the method of creating solutions to people's problems by imitating nature, is something we’re only getting better at. Scientists are now looking to the building blocks of mushrooms to solve the world’s plastic pollution problem, and the science behind the emerging technology is nothing short of fascinating.
Mycelium, the underlying fungal foundation of mushrooms, is a fine network of tubular filaments sometimes just a single-cell in thickness that is similar to yeast. Mycelium takes in nutrients from dead trees and other plants via the secretion of digestive enzymes and can arrange the molecules it produces into incredibly complex structures.
Ecologist Suzanne Simard’s groundbreaking work over the last 35 years has shown that mycelium creates a kind of structure that allows large networks of trees and other plants to exchange nutrients underground and even communicate information about parasites and other predators to their neighbors. This helps to give an idea of mycelium’s potential scale: Some fungi have even been found to cover an area of roughly 2,384 acres (965 hectares).
Once far enough along in its life cycle, the mycelium forms a fruiting-body, the umbrella or gourd-shaped fungus that grows above-ground and that we call mushrooms.
“Mycelium based materials are inherently nature compatible."
It’s at this point that scientists have stepped in to harness the power of the fungus. By controlling CO2 levels, temperature, and humidity conditions, mycelium growth can be directed to form predictable macro-structures in a matter of days. As Scientific American points out, the accumulation of these fibers can produce “an 18-by-2-by-12-inch sheet weighing a couple of pounds within the course of a week.”
Plastics out, mushrooms in
Harnessed properly, these structures have the potential to be used in a myriad of real-world applications, and companies around the world are starting to explore their potential to replace petroleum-based materials in industries ranging from packaging, apparel, and even construction.
This is an encouraging example of economic incentive creating more space for eco-friendly pursuits. The global packaging industry alone is estimated to grow to over $50 billion by the latter half of this decade.
One organization tapping into both the technical and economic potential of mycelium is Ecovative Design, a New York-based materials design company that has made impressive strides in showing what the technology can do.
Founded in 2007, Ecovative has focused on “closing the loop” of materials production so that its products can return to the earth instead of piling up in landfills or interfering with natural ecosystems.
“Mycelium-based materials are inherently nature compatible, so at the end of their useful life cycle, they can be passively returned to the earth,” explained Ecovative co-founder Gavin McIntyre in an interview with Interesting Engineering. “The biochemical backbone of mycelium [is] chitin, the same biopolymer in lobster and crab shells.”
Polymers like plastic are good at what they do. Too good, as the world has come to learn, with the average plastic bottle taking anywhere from 200-500 years to fully decompose. For McIntyre, critiques that a biomaterial like mycelium might not hold up as well as petroleum-based products in usage or lifespan actually represents part of its virtue.
“The degradation of the material occurs when you put [the product] in the dirt. Compostability is the active degradation of a material by the soil biota. That’s bacteria, fungi, [and] protists that live in the soil and have the enzymatic capability of breaking these materials down. So, putting [mycelium] into a built environment or clothing, that’s not something that’s going to have that type of effect, but if you break it up into small pieces, put it in the dirt, it’ll passively return to the earth in about 45 days.”
A mushroom of all trades
The process underlying mycelium production also enables companies like Ecovative to grow a wide range of products, from tough, leather-like textiles to meat substitutes.
In terms of resources consumed and measurable harm done to the environment, the meat industry has long been a significant offender. So much so that in 2019, the EAT-Lancet Commission released a report stating that in order to effectively combat climate change, red meat consumption needs to fall by 90 percent.
That’s a tall order, but it’s one that mycelium could end up playing a significant role in realizing. Companies around the world, like the Spanish startup Innomy and the Colorado-based Meati Foods, are working to develop mushroom-based meat alternatives in hopes of changing consumer eating habits and reducing the industry’s negative impact on the environment. It’s a trend that Ecovative has been working on as well, having set its sights on what might be the crown jewel-favorite of meat lovers: bacon.
“We’ve seen a lot of new product development in the plant-based meat category, generally. The challenges with those products today is that they mostly focus on ground meat alternatives, things like burgers and sausage, which is still a meaningful portion of the market, but smaller than that of whole muscle meat, things like steak, bacon, and fish fillets, the products that most folks in the world consume on a daily basis. That tends to command more than 80% of the market here in the United States.”
Using gourmet mushroom species, Ecovative is beginning to deliver just such whole-muscle meat replacements.
Growing better buildings
Mycelium can also be used as an industrial building material. The construction industry is thought to account for just over 10 percent of the world’s carbon emissions, a significant portion of which comes from cement production. This is one of the industries that Ecovative first set its sights on.
"If you maintain mycelium’s bioactivity, it could actually self-repair."
“We've only been around for 15 years. One of our first product applications was in the built environment as rigid board installation,” said McIntyre.
Rigid board insulation is often used to regulate temperature and reduce a building’s energy consumption by closing off areas where air might be leaking through a structure.
As Ecovative grew in size and capacity, government agencies like the Defense Advanced Research Projects Agency (DARPA) took note of what they were doing with such material and approached the company for a partnership.
“DARPA came to us with a very interesting problem, and that problem was that if you look at areas that require rapid relief, areas that were hit by a natural disaster, oftentimes rebuilding in those areas takes a tremendous amount of time and cost because you have to import all of these materials.”
“One of the wonderful things about mycelium is that you can decentralize its growth, and actually do infield cultivation of materials, taking local resources and transforming those into the building materials for the next generation. If you maintain [mycelium’s] bioactivity [...], it could actually self-repair. So, over the last four years now, we've been collaborating with a number of university partners under a DARPA program to build out a toolkit of materials that could be grown in-field and actively self-repair when damaged,” said McIntyre.
The company has also done work with Oak Ridge National Laboratory, a research facility sponsored by the US Department of Energy, demonstrating their construction materials’ ability to survive in any environment in North America for a period of no less than 30 years.
If the techology continues to be developed, it could become a viable and common home construction material in the near future.
Forming a future with fungi
There is a lot to be excited about regarding mycelium, but like any material, it has its limits as well. One of those limits is the amount of water it may absorb, which McIntrye acknowledges is a benefit for plastic foam alternatives but could be problematic in other situations.
“All of our products are open-cell structures. [...] Just like any other natural material like wood, these materials will absorb water if they’re fully immersed in water. It is a consideration for other types of durable goods, and that’s an area that we are evaluating,” he said.
A 2020 study published in the journal Materials & Design echoes those words. The study’s authors acknowledge that while mycelium building materials feature better fire safety properties and have lower thermal conductivity than traditional materials, their foam-like mechanics limit their applications. It's also been suggested that mycelium biocomposites risk contamination by bacteria and mold.
Despite these issues, McIntyre and others are optimistic about mycelium’s future, and it’s not hard to see why. The material does indeed seem to check off many of the requirements that scientists and climate advocates say need to be met in order to significantly reduce human impact on the environment while featuring a host of other benefits in each field it can be applied to.
If the technology can indeed swap out harmful plastic products with cheap, biodegradable, eco-friendly alternatives and reframe consumption habits in the process, we may have developed a tool to help ensure a more stable, sustainable future for the planet.
McIntyre invites people to “think of all the polyurethanes that are used in the automotive industry, the apparel industry, those are materials that could be substituted by mycelium.”
“Even looking at construction-grade materials,” he continues. “We have certain materials that can be as tough and strong as balsa wood but have isometric properties so that they are consistent no matter which direction you pull or push on them. When you think about trees, they have a grain, they have a vasculature. Your performance deviates depending on which direction those fibers are laid. Using [mycelium], we can influence those fiber structures and get some really interesting properties. For next-generation wind turbines, vehicles, that’s an interesting area to explore in the future.”
Versatility often equates to increased functionality. The more we explore biomimicry and use nature as a base from which to better treat that nature, the more sustainable a world we can create. And the humble mushroom might just be what helps get us there.