April 18, 2020
A fungus Trametes versicolor. According to researcher David Dussault, the mycoremédiation allows to reduce the costs related to the landfill.
This text is part of the special Earth Day
“The mushrooms are the slicers of the molecular world,” recalls David Dussault, mycologist, and environmental specialist. While the landfills are overflowing, the researcher postdoc is interested in this completely natural way to break down the waste, and in particular textiles.
Compacted and buried in an oxygen environment, textiles can take hundreds of years to biodegrade in landfill sites. Not to mention that “more and more textiles are made from petroleum products or are a mixture of fibres, and are, therefore, hardly degradable,” explains David Dussault. The use of mushrooms to clean the soil, or to the mycoremédiation, was already known. And if the mushrooms were able to “digest” the textile-based hydrocarbons, it is asked ?
Tons of textile
The textile occupies a prominent place in our waste. According to Recyc-Québec, nearly 190,000 tons of textiles are discarded every year in Quebec. It is 24 kg per household ! Less than 40 % of textiles are recovered, which represents a major problem in the environmental point of view, in addition to generating significant costs for businesses, which must pay to bury these textiles.
Since 2013, David Dussault works with the body Certex, which recovers and recycles the textiles. In the framework of his phd, he tested several “recipes” for getting to find the correct variety of fungal species and the right conditions to ensure that decomposition is effective of these textiles recalcitrant. “I don’t want to be just another application in engineering. I also wanted to have a biological approach, which would have a solution in adequacy with the environment, ” he says.
The avid mushroom has bought elsewhere in 2016, a farm of edible mushrooms in Saint-ours, which he renamed Mycocultures.
His new company, Myco Innov, founded in 2019, will be devoted to the testing of biodegradation of these substances with the help of fungi. Following Certex, David Dussault plans to work with the treatment centers, landfills, or the industrial production of parts.
It is the mycelium, these white filaments branched, forming the vegetative parts of the fungus under the earth, which is responsible for the process. You mix the mycelium with waste textiles, such as nylon or polyester, and with a substrate that will feed the fungus : agricultural residues, which resemble straw, wood, or even food waste plant in canning. It sterilizes everything, and left for the fungus to act. After the first trials, which produced a very good degradation in three months, David Dussault has refined his method. Today, “we get a degradation incredible, almost a mineralisation, in a few days,” he says. Most of the textiles made from hydrocarbon break down easily, except maybe the PVC. With its atom of chlorine, it is much more recalcitrant than the polyurethane or plastics.
But there’s more. By stopping the process fungal and heating the mycelium, then it can be molded into a multitude of products. “The mushroom networks materials, streaked and discolored,” says the researcher. Result ? A material that is white and homogeneous, the texture is close to the polystyrene foam which, when hardened, could be used in aircraft, to make bumpers, packaging or insulating panels.
David Dussault has made flower pots, and are also working on prototypes of garden furniture. All without glue or epoxy, as it is the mushroom that makes the link between materials. The objects remain resistant for many years if you do not expose them to moisture levels that are too high, but can also be completely degraded at the end of life.
As a way forward ?
Following the principle of the circular economy, this technique of degradation of waste enables the upgrading of waste materials, decrease the costs related to the landfill and reduce the energy expenditure, as it is the mushroom that gets the job done. In the United States, few companies are exploiting this material, including Ecovative Design, which produces boxes and transport packaging for large companies like DELL and IKEA. The company has also developed a material that is completely biodegradable with a texture more like a sponge, which can be used as textile or skin care. A firm of architect american even designed the Mycohouse, a prototype of a house made entirely of this material live, without the need to use glue or binder.
Why, therefore, this technique is not more prevalent today ? “The problem is scaling,” says Mr. Dussault. In manufacturing, for example, insulation panels, we find ourselves in competition with the great ones of this world, such as Dupont. Even if in the end this new technique is less expensive and complicated, “in Canada, no company has done this to the scale,” he observes.
While the planet has to suddenly think seriously about the mode of consumption, the biodegradation of the textile by this natural process becomes a way of future interesting. “I am of the opinion that this is what should happen ; it should have the least possible impact on our planetary system “, concludes the mycologist.