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The Art and Science of Mycoremediation


myco-

Derived from the Ancient Greek word μύκης (mukēs) meaning “fungus”, referring to anything related to fungi.


-remediation

Derived from the Latin word “remedium”, meaning, “restoring balance”


Put the two together, and you end up with mycoremediation - the practice of using select species of fungi in a controlled manner to restore balance to damaged ecosystems. You may have heard of the term “bioremediation” - a much broader practice of using living organisms (bacterial, botanical, etc.) to decontaminate landscapes and waterways. It is the fungal aspect of remediation that I want to focus on, because it offers specific solutions to many of the ecological problems we are facing in modern times.


The consequences of many decades of humans’ exploitation of natural resources and the maltreatment of ecosystems are creeping up on us at an ever-increasing rate, and as each new generation comes to life into a more and more toxic world, there is more pressure on us to repair the damage that has been done. What ecological damage am I referring to?


Oil spills, soils contaminated with toxic pesticides and herbicides, artificial fertilisers and factory-farmed animal wastes washing into streams and rivers, gardens unfit for growing food due to excessive levels of lead from roadside pollution, and much more - not all of these scenarios are encountered by us individuals on a daily basis, but they exist, and their impact on our health, the health of future generations, and the health of the ecosystems on which we depend are beginning to stamp their marks on our business-as-usual ways of living. Taking into account that much of this damage has already been done, we must begin to not only think of ways of reducing current pollution levels, but also healing the ecological wounds from this pollution. Here is where fungi come into the picture.


Fungi have the incredible ability to decompose and shuttle away, a wide range of biological and chemical pollutants. Compared to the very energy- and cost-intensive methods of remediation employed by industry nowadays, mycoremediation offers an inexpensive, low-tech, and grassroots way of restoring damaged landscapes that, as a result, can be put into practice more readily and frequently, making it a much more effective option. With each discipline, one has to learn the tricks of the trade, and in this introduction, I will attempt to simplify this vast discipline into an easy-to-understand format. To begin, we will look into the biology of two main types of fungi most frequently used in mycoremediation.



Saprophytic Fungi

For over 500 million years, long before the formation of animal life on Earth, it has been the ecological role of many fungi to break down dead organic matter, converting it into its own tissue before returning newly-formed nutrients back into the ecosystem as soil. In other words, these “saprophytic” fungi evolved to feed themselves by salvaging the remains of once-living creatures, some of which contained large, complex chemistries that posed an evolutionary challenge to these fungi. How to crack the chemical codes to break down these large molecules was the task at hand, and over the span of millions of years, these chemical codebreakers have amassed a repertoire of enzymes capable of tackling the most toxic of pollutants in this new era the world is heading in to.



The oyster mushroom (Pleurotus ostreatus) is the saprophytic poster child of mycoremediation due to the aggressive nature of its mycelium.

By making use of this spectacular property of saprophytic fungi, we can guide and steer the growth of certain species to acclimate themselves onto novel contaminants, helping to decompose toxic substances at a much faster rate than would ever be possible without human intervention. The end point of this process can vary: sometimes the contaminant can be reduced to low enough concentrations so as to be effectively harmless, and sometimes it is broken down into smaller, yet still harmful, substances that require the help of other remedial organisms such as bacteria.


Mycorrhizal Fungi

At some point in time, there sprouted a new branch in the evolutionary tree when new species of fungi began to source their nutrition by forming partnerships with plant roots, to which the fungi channeled minerals into, in exchange for sugars that the fungi needed. These “mycorrhizal” fungi became adept at mediating nutrients between soils and plants, forming vast underground networks that regulated nutrient flows and stabilised ecosystems. The fascinating aspect of mycorrhizal fungi is their ability to absorb and channel heavy metals such as mercury, arsenic, cadmium, and radioactive caesium, before concentrating them in the flesh of their mushrooms. That way, any heavy metal contaminants spread within the soils of an ecosystem can be channeled up to the surface of the ground within the body of a mushroom, before being carefully removed by remediators and processed in specialised facilities. In time, the concentration of toxic metals falls and becomes safe again.


With that being said, this is only a brief, and somewhat simplified overview of the types of fungi used in mycoremediation, and there is in fact a degree of overlap with their functions. For example, the Pearl Oyster (Pleurotus ostreatus) is by nature a saprophytic mushroom, but also has the ability to upchannel heavy metals into its fruiting bodies.



So how does this process work? By cultivating fungal mycelium on optimal substrates (such as wood chips, sawdust, cardboard, etc.), they can be expanded and propagated into ecosystems where they can begin the process of remediation. This can take the form of:

  • introducing mycelium of saprophytic fungi to contaminated soil to begin the process of breaking down petrochemical contaminants

  • immersing myceliated substrates into water systems to help filter out biological contaminants

  • inoculating soils and plant roots with myceliated substrates to expose mycorrhizal fungi to heavy metal contaminants, and upchannel these into its fruiting bodies

as well as any combination of these that are more species-specific. Again, this is a very simplified overview of how mycoremediation can be applied, with some species being only suitable for particular strategies and particular contaminants. It is the responsibility of the remediator to research which fungus would be most appropriate for their situation. With the application of this knowledge can come a regenerated ecosystem and a renewed sense of community within the natural world.



As a final note, I would like to take a step back and view mycoremediation not just from an ecological perspective, but from an evolutionary one. We humans have interacted with fungi for millennia, but mycoremediation is a novel partnership that has arisen only in the last few decades by necessity, and it comes with massive implications. I personally believe that the embrace of mycoremediation is a new relationship between humans and fungi that may become as important to us in the future as the relationship between flowers and bees.

By cultivating and propagating fungi across landscapes, humans increase and sustain the populations of these fungi, and over time, select for the species that will thrive the best in these novel chemical environments they are being immersed in. In return, the fungi provide human and other-than-human life with safe and habitable environments, and thus, help sustain our species too.


In biology, this kind of cooperative partnership between different species in which all parties benefit from the work of the other is known as symbiosis. Faced with an ecological problem of global proportions, we partner up with the fungi and create a new ecology, a stronger link in the web of life which serves to improve the wellbeing of all living creatures. This partnership may just be the key to helping us thrive in an uncertain future, and those who forge a relationship with fungi may be given an evolutionary advantage over those who do not. Nature rewards interconnection. Yes, the damage we are trying to repair is the result of centuries of our own reckless behaviour, but as remediators, we do not mire ourselves in the problems but instead, actively work towards the solutions.


Making mycoremediation a keystone practice in society will be a herculean task, but the easiest way for it to begin will be through the conscientious efforts of communities of grassroots remediators, equipped with the practical knowledge of this craft, and the willingness to strive towards a world in which we live in balance with the rest of all life, and on that note, I wish you all the best in your exploration in this exciting field of mycoremediation.

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