Using fungi and their extraordinary characteristics to “grow” construction materials and degrade pollutants: this is the vision underpinning many studies that soon may lead to real applications while making circularity truly “biological”.

Aliens amongst us and inside us. Omnipresent and largely yet unknown. Architects of life on Earth, we actually ignore and have underestimated their real and mysterious influence for a long time.
Fungi are literally everywhere: from invisible yeasts and moulds, colonising our own body, to tentacled Armillaria ostoyae, the largest living organism ever discovered, stretching nearly over 10 km2 in Oregon’s woods and mountains. They can live on rocks, ocean floors, deserts, in the middle of the arctic ice, on tree leaves or in animals’ bowels. There are between 2 to 5 million estimated existing species, but Paul Stamets, the American guru of mycology, reckons there may be even 10 millions. And yet we barely know (and not even that well) 120,000 of them. Indeed, there is no agreement when it comes to classifying the kingdom of fungi, suffice it to think that the species Pleurotus ostreatus (the common wood-decay fungus or oyster mushroom) contains thousands of strains differing from each other genetically by 12% whereas the genetic difference between humans and chimpanzees is a mere 2%.
In a nutshell, about 95% of fungal species is currently an unknown universe. The analogy with the state of contemporary physics research describing the Universe as composed of 95% of “dark matter” and “dark energy” is disturbing as well as astounding.
According to Merlin Sheldrake, a young biologist who authored the global bestselling book Entangled Life: How Fungi Make Our Worlds, Change Our Minds & Shape Our Futures, with fungi and microorganisms we are entering the domain of “biological dark matter or dark life.”

Mycelium and the Internet of Forests

Despite such conundrum, we have managed to understand a little something about them and recently we have even started to sense something else.
First of all, we should make a distinction: what is commonly known as a “mushroom” it is actually just its fruiting body, i.e. the means by which spores are produced and through which the fungal organism reproduces itself and spreads out. The fruit is just a part of a bigger and more complex structure, made of cell networks called “hyphae”, long intertwined filaments forming the real body of the fungus: mycelium. “Mycelium – observes Sheldrake – describes the most common of fungal habits, better thought of not as a thing but as a process: an exploratory, irregular tendency.” Indeed, through mycelium networks, fungi travel, expand, create connections, carry water, nutrients and, as recently suggested, even information. The first to talk about Wood Wide Web, in the mid 1990’s, were biologists David Read and Suzanne Simard, starting from a few experiments on mycorrhizal networks shared between fungi and plants in forests. Mycorrhizae – a term derived from the Greek words “fungus” and “root” – are the perfect example of mutual relation, symbiosis, in nature.
Plants and fungi have a sort of collaboration that is as old as life on the planet. As a matter of fact, plants came out of water 500 million years ago thanks to a collaboration with fungi that lent themselves as root systems until vegetables started developing their own. And today such co-operation still goes on: fungi take carbon from trees in its glucose form thanks to photosynthesis, while trees take their nutrients such as phosphorus and nitrogen, which fungi absorb from trees thanks to their specific enzymes. But it would appear that such exchange does not stop here. According to Sheldrake and colleagues, we have only just started to grasp the possibilities and functions of the Internet of forests and more generally mycelial networks that, apparently, convey real “messages” in the form of chemical substances (infochemicals) or electric impulses, for instance to warn against an infestation of a certain parasite. There are even those, like Paul Stamets, who speculate that the underground fungal network might act as the planet’s immune system (and thus even ours), which is all the more reason to commit to not destroying ecosystems.

The Art of Metabolism

While an understanding of fungi connecting super powers is only in its early stages, we know their metabolic prowess slightly better. “Metabolism is the art of chemical transformation. – writes Sheldrake – Fungi are metabolic wizards and can explore, scavenge, and salvage ingeniously, their abilities rivaled only by bacteria.”
Thanks to such ability they can be regarded as real architects of our ecosystems. Going back to how life came into being on the mainland, for example, it was lichens – an association of fungi with algae or bacteria – that by “digesting” bare rocks transformed them into humus, thus creating a nutrient substrate for plants.
Today, most studies exploring possible fungal applications focus on their transformative ability. One such example is the Fungal Group of the Faculty of Microbiology in Utrecht, coordinated by Professor Han Wösten. One of the most promising fronts is wastewater treatment. “We use the same enzymes used by fungi to degrade lignin that, besides being the second most widespread biopolymer on Earth, in quantity, after cellulose, is one of the hardest to decompose – explains Wösten to Renewable Matter –. These enzymes, that literally bombard lignin to decompose it, can do the same with other substances such as polycyclic aromatic hydrocarbons (PAH) which constitute the basic ingredient of many industrial chemical products such as pesticides, dyes, pharmaceutical or personal hygiene products and steroid hormones. The waste treatment plants currently in use are not able to degrade such micro pollutants in an effective way; they thus end up in rivers with serious risks for health and ecosystems”. As things stand, research is still in its experimental phase: Wösten and his collaborators are trying to achieve full molecular degradation in order to avoid any toxic waste at the end of the process. There are actually great and exciting prospects for practical applications.

Resisting Industrial Agriculture but Friends of Circularity

Anyhow, fungal metabolic abilities are widely exploited, even if kept rather quiet. Just think of citric acid, for example, used in most industrial beverages, including the most famous of them all: “It is certainly not derived from Sicilian lemons – says Wösten – but it is synthesized from fungal enzymes.” Just as nearly 60% of enzymes used in industries around the globe to manufacture detergents, additives and even substances to decolourize jeans to obtain the so-called “stone-washed” effect (“it is not actually achieved with stones”, specifies Wösten).
Then there is the whole chapter of pharmaceutical industry that from penicillin onwards has heavily relied on fungi. For vaccines only, “fifteen percent of all vaccines are produced by engineered strains of yeast,” writes Sheldrake. Furthermore, there are immunosuppressants to avoid transplant rejection, statins to keep cholesterol under control, several antiviral and antitumor compounds and psylocibin, the active principle naturally occurring in the so-called psychedelic fungi, recently approved by some clinical studies that demonstrated its effectiveness as a cure against depression and anxiety. The market of medicinal fungi is growing year after year and goes hand in hand with that of edible fungi (including fermentation yeasts). Their market value was estimated at around $ 42 billion in 2018 and is expected to reach almost 69 billion in 2024.
And yet, despite the multi-million dollar industry they foster, fungi are little rebels, resistant to large-scale projects. “The number of species we are currently able to grow is still very low – explains Wösten –. Most of them do not grow in captivity, including porcini mushrooms: this is why we are still picking them in woods. The thing is that we still ignore the exact process and conditions that make a fungal organism bear fruit. Amongst other things, this is what we study at the University of Utrecht, so as to optimise their production”. We may now wonder if a hypothetical large-scale fungal production would not risk falling prey of the same unsustainable practices of industrial agriculture. But Professor Wösten has great confidence in fungal skills with regard to the circular economy. “The good news – he says – is that to grow fungi we can use waste matter, such as low-quality straw which cannot be turned into feed, horse manure or other kinds of waste that cannot be reused. Low-quality matter flows are thus transformed in high-quality food, since mushrooms not only taste good, but they also contain protein, minerals, vitamins and activate your immune system.” Another plus is that they grow even in degraded or not very fertile soils, they do not need fertilizers and they actually regenerate soils. “Mycelium ‘colonizes’ straw on which it grows and once mushrooms are picked, such material becomes good compost to nourish the soil, which, by the way, – as Wösten concludes – is what fungi do in nature when they biodegrade dead trees while producing nutrients for the ecosystem.”

Farming Matter: The Growing Design

If we move from fungi’s chemical, metabolic and nutritional properties to their characteristics as builders, we enter a realm of endless possibilities. Maurizio Montalti knows it only too well: with his Officina Corpuscoli Lab in Amsterdam and his start-up Mogu in Varese (Italy), he started what he defines a “collaborative relationship” with mycelium to grow the materials of the future.
His work – a cross amongst engineering, design, and microbiology – started over ten years ago in Professor Wösten’s lab in Utrecht. “Han was one of the few people to take me seriously, giving me the chance to experiment with my ideas,” he says. The two literally started growing materials cultivating fungi on straw substrates and then they used mycelium “colonised” straw as heat insulation, for instance, to replace mineral wool. Depending on fungus species characteristics, substrate used, environmental and growing conditions, different types of biomaterials can be obtained with characteristics similar to plastic, rubber, wood, paper, cork, leather or foam used for packaging. “Sky is the limit! With fungi you can make anything,” Montalti says. Research is going ahead both in Amsterdam and in Utrecht, and he has found a commercial use (one of the very few at the moment) thanks to Mogu, which produces insulating panels and flooring materials made with mycelium grown on agricultural waste or textile residue substrate in a perfect circular rationale.
Montalti called this process “growing design” to highlight the radical difference compared with building or assembling. “Sometimes, to provoke me, some people ask, ‘But who is the designer, you or the fungus?’ To be honest, I must admit that fungi are the designers. I am just like a choreographer giving directions, but they do the work.” And when he talks about “collaboration” he is not speaking metaphorically, he means his words: it is this inter-species cooperation that makes these mycelium-based materials so peculiar. “The idea of growing,” he explains, “entails a real communication and interaction relationship with the non-human organism we cooperate with. We obtain a living material telling the story of a growing process. Nothing to do with inert materials normally surrounding us, which say nothing about their origin.”
Anyhow, it is not just a question of aesthetic sensitivity. A living material, such as that produced by Officina Corpuscoli’s experiments, offers a series of incredible possibilities and characteristics, such as the ability to self-reproduce and self-regenerate. Or rather, it would offer, since the market is definitely not ready for this novelty. “What I do at experimental stage is to let mycelium grown radially on its substrate, when it gets to the point I want, I stop the process by altering environmental conditions”, Montalti says. “Essentially, it is like hibernating the fungus. But if, for instance, the panel obtained breaks in two, I could restore growing conditions and the mycelium would create a suture. The problem is that the current market only wants stable and inert materials. It wants dead materials; this means that to sell panels I must kill mycelium. I feel sorry for it and it is a pity for all the possibilities that are lost.”
Even if the market is slow, the vision of a grown world instead of a built one broadens to imagine entire buildings made of living matter, growing and interacting with the environment, transforming over time, instead of being built, assembled and dismissed. This is the idea of Fungal Architecture – a European project where Montalti takes part with Mogu – aiming at building mycelium monolithic structures capable of reacting and adapting to environmental conditions and pollutants. After all, something that already existed 400 million years ago when Prototaxites, fungal organisms as high as two-storey buildings, offered shelter to insect colonies. Living palaces in other words. Are we ready?

Download and read the Renewable Matter issue #37 about Food Systems.

Image: Mycelia, ph Maurizio Montalti