Did you know that the largest living organism on Earth is not the whale, but a species of fungus? According to the Guinness World Record, the gigantic mushroom found in Oregon weighs more than 6000 tonnes and spans 9.65 km². Mushrooms may not seem big, but we usually only see the fruiting body— what’s above ground. Underground, you find fungal threads called hyphae, which come together to form a vast network of mycelium. Fungi have been of great service to humans throughout most of history. From providing a food source to fermenting bread and alcohol, its uses are only getting broader. For the modern world, the most exciting innovation in fungi is the control over their mycelium growth to construct packaging and building materials. These “mushroom bricks” are of interest to many investors and environmentalists — but there are still hurdles to overcome before widespread implementation is possible.
The first step in growing mycelium material is to provide it with food, or raw materials. These can be carbohydrates (wheat, glucose), industrial waste (sawdust, wood chips), or anything with nutrients for the fungi. Once the raw material is selected, it is then soaked with water, and then milled into smaller pieces to increase surface area. To make the fungi grow better, the ground raw materials undergo heat or chemical treatment to remove any microbial competition present. Following that, the treated raw material is transferred into a cast that will become the final shape of the mushroom brick. Finally, spores or fungal parts are added.
While the fungus is growing, it can be stored at room temperature but can grow faster at higher temperatures. The time it takes for the mycelium to finish growing depends on the desired level of bonding, type of raw material used, and the fungal species employed. Combined, these factors make the growing times vary from days to months. When the growth is complete, the material is taken out of the mold, hot-pressed, and finally dried. Hot-pressing the material can both harden it more and neutralize the fungal cells, so they don’t grow anymore when in use.
The use of mycelium material in packaging and even architecture makes it an interesting rival to both plastic and concrete. Plastics of all kinds are used extensively in packaging, but if not disposed of properly, can pose great threats to the environment. Mycelium material, on the other hand, is purely organic, making it readily decomposable. The manufacturing of mycelium material is a natural process, takes little energy, and removes CO2 from the air. Similar to mushroom farming, growing mycelium is relatively carbon-efficient, producing only 0.7kg of CO2 per kg of mushroom. On the other hand, cement, a key ingredient in the production of concrete, produces 0.66 to 0.82kg of CO2 per kg manufactured. It is also very energy-intensive as it requires temperatures greater than 1400°C during the heating process. It should also be noted that growing mycelium is even more carbon-efficient than mushroom farming due to the prevention of fruiting body growth, since a lot of energy is used towards the visible part of the fungi. The controlled manufacturing environment during the preparation phase also optimizes the growing time and amount of energy required.
Because it is a developing technology, mycelium material still has its shortcomings. When used in building, the mushroom bricks are significantly less durable than concrete in terms of compressive strength, greatly limiting the size and durability of structures. It is hypothesized that adjusting both the raw material feed and growth temperatures may optimize the mycelium’s growth and mechanical properties, of which further investigations will need to be made. In the packaging market, mycelium materials are only being used by a select few companies (Ecovative Design, Paradise Packaging, etc). The plastic production industry has already matured, lending a competitive edge to both market availability and reputation. Companies in the mycelium materials sector are still regarded as ventures, the risk of which could discourage investors from providing more funds.
Mycelium technology on a whole still faces many problems, and much research is required to develop this technology further; however, because it offers an environmentally friendly alternative to plastic and concrete, it has the potential to gain serious traction in the market. This is not to say that mycelium materials will completely replace plastics and concrete, but rather reduce their environmental impacts by reducing the need for them. The best thing that the public can do is to keep an open mind about this living technology, and give it a chance to grow in the uncertain future.