Fungi & The Plastics Problem
Fungi were the first colonizers of the planet. One billion years before the introduction of plants, fungi thrived on the land in vast mushroom forests. However, they have since evolved to fill countless niches in ecosystems around the world, becoming, in a way, the planets most adept stewards. Fungi are the strong and silent caretakers of the forest, channeling nutrients and water to plants with their dense networks of mycelium. They are the great disassemblers of matter, creating fresh soil for new growth from the tissue of fallen trees. Fungi promote the healthy succession of species through nutrient cycling and the thinning of diseased organisms that stops infections from spreading. Their robust immune systems produce powerful compounds that serve as medicine for humans and other animals. And their multi-dimensional symbioses with countless plants, animals, and microorganisms exemplify the interconnectedness of all life.
As the most widely colonizing species on the planet today, humans can find no better natural role model than the fungi when looking to better understand patterns of ecological success. For the wisdom provided by these ancient land-based organisms may very well offer solutions to the many problems produced by the most destructive species of our time: ourselves. Human relationships with fungi have taken many forms over the centuries. Vision-inducing mushrooms have long been consumed in search of spiritual and social guidance. In an age where science is called the newest religion, perhaps we may find similar help through our modern trials by seeking answers in the ecology and chemistry of fungi. As the fungal colonizers have in their age come to be the great harmonizers of their environment, so too can people in western cultures of domination learn to solve the problems they have created by shifting their lifestyle from one of control over nature to a more sustainable, egalitarian, and venerable one.
One of the greatest man-made problems facing future generations today is the ever-increasing glut of plastic waste filling the world. Plastics are now humanity’s number one source of pollution, accounting for an estimated 20-30% (by volume) of municipal solid waste in landfill sites worldwide (Ishigaki et al 2003). More than 140 million tons of plastic were manufactured worldwide in 2001 alone (Cosgrove et al 2007, and the numbers keep growing. Some plastics are estimated to breakdown over a period of several thousand years, all the while leaching toxic compounds such as BPA (a persistent carcinogen and endocrine disruptor commonly used in plastics production) into surrounding soil and groundwater. Furthermore, the water repelling nature of some plastics has been reported to attract and concentrate toxins, thereby forming reservoirs of toxic chemicals in the immediate environment (Roy et. Al. 2011).
Outside of the landfill these plastics-induced problems compound. Wherever plastics are discarded, plants and animals become affected by this toxic leaching. Along roadsides, in forests, and, more silently, in the great oceans of the world plastics leave their mark. In every ocean there are vast “trash islands” where sea currents naturally cancel out, causing the waters to stagnate and subsequently accumulate plastic waste floating in from shores and ships. Due to the effects of tidal forces and the intense UV radiation from the sun, the plastics in these areas, known as gyres, are being perpetually broken down in to smaller and smaller pieces. These gyres become a plastic soup filled with toxic residues and microscopic plastic particles several meters deep.
When fish swim through these cesspools, they often confuse the plastic fragments for plankton, a mistake that severely disrupts marine food webs (Thompson et al, 2004). Sea turtles eat plastic bags thinking they are jellyfish, only to suffocate. And albatross birds feed their babies brightly colored lids that they confuse for fish, resulting in huge fatalities to their population. All oceans have such plastic “patches,” however the largest of these is located in the northern Pacific Ocean. Known as the Great Pacific Gyre, this famous patch is estimated to cover a surface area the size of the state of Texas with a depth of 10 meters.
Recycling is often considered the best option for dealing with the plastics problem, but it doesn’t represent a complete solution. Eight percent of plastics are thermosets, which means that they can’t be remolded or recycled (Zheng & Yanful, 2005). The other main type of plastics, thermoplastics, that can be recycled, but require careful sorting (a cost-intensive process most governments can’t afford, or won’t pay) and results in an inferior plastic with lower economic value. Even so-called “biodegradable” plastics are not all they are cracked up to be. Though the chemical structure of these biodegradable plastics has been modified to supposedly help increase the speed of decomposition, research fails to prove the efficacy of this strategy in the landfill. Real solutions to the plastic problem need to be investigated and improved upon.
- All this plastic was found in the stomach of one albatross bird
Enter the fungi. Through their co-evolution with plants and animals over millions of years, the fungi have come to fill several roles in nature, one being as primary decomposers, responsible for 90% of all decomposition on the planet. The decomposing, or saprotrophic, fungi survive by excreting powerful enzymes to breakdown the molecules of organic matter into simple sugars that they use as food. Similar to how a fly eats, the fungi digest externally and then ingest their food as a liquid. The connection between death and new life is made literal by the fungi in this nutrient cycling that enables new plants to grow from the byproducts produced by the decomposition of dead organisms. Fungi (in the form of lichens) can even break down bare rock to be used as a nutrient source, in effect creating the precursors of soil following lava flows and landslides. The digestive enzymes fungi produce are so refined and powerful that it has become increasingly apparent that fungal species can be targeted for their ability to utilize seemingly anything natural or synthetic as a food source.* This theory has proved itself in recent years against even the most persistent chemicals of the green revolution. Nasty compounds such as DDT, dioxins, TNT, PAHs, herbicides, and synthetic dyes, once considered impossible to clean up, have been shown to readily fall prey to the chemical sword of these fungal metabolites (Stamets, 2005).
Not surprisingly, then, is the fact that this same ability applies to plastics as well. However, this is not necessarily a recent realization. Plastics have been known to be susceptible to fungal degradation since they were first manufactured and tested over 100 years ago. Early on, plastics manufacturers began testing their products to determine the longevity of plastics in comparison to the wood, metal, and glass objects they were meant to replace. One such test involved simply burying pieces of plastic in the ground and seeing what would happen. Sure enough, when the pieces were dug up a year or two later, the experimenters found fungi and bacteria digesting the plastics and decreasing their integrity. The basic form of this experiment has been repeated around the world numerous times in the decades since, each with tests finding similar results. In some experiments, scientists would even go a step further by taking the colonized plastic pieces, isolating the various bacterial and fungal species growing on them, and then testing each species for its individual degradation ability. While this research unearthed several species and genera well suited to this task (one study even confirmed that it was the fungi, not the bacteria, that were the main contributors to this process), little progress has been made in 100 years toward developing a method applicable outside the lab, let alone in the landfill.
One strategy for solving the plastics problem with fungi is to grow the fungi under relatively simple conditions to then isolate their digestive enzymes en masse. At a high enough volume, these liquid enzymes could then be applied directly to waste plastic to begin the process of degradation on a large scale (Russell et al 6081). This might sound bit far-fetched, but it is essentially the same process through which citric acid is produced by the mold Aspergillus niger for the food industry.
At Yale University, undergraduate students have in fact applied this process with positive results to polyester polyurethane, a type of plastic commonly used for textiles. This study was particularly remarkable for the fact that instead of focusing on ground-dwelling or even saprotrophic fungi, the students took the novel approach of using an endophytic fungus. This type of fungus lives inside of plants (literally between the plant’s cell walls), cohabitating with the plants for reasons largely unknown. Little is known about the use of endophytes in fungal remediation, so when the Yale team applied enzymes harvested from the endophyte Pestalotiopsis microspore (isolated from a plant in the Amazon jungle), their positive results were astonishing. Not only could this endophyte survive off the plastic as its only carbon (i.e. food) source, but it could this do both in the presence and absence of oxygen. These findings help overcome one of the major roadblocks to real-world application of plastic degradation using fungi, which is that most ground-dwelling fungi cannot survive in anaerobic areas such as landfills.
Endophytic fungi are potentially one of the most diverse categories of fungi (with any given plant possibly containing hundreds of species of them), yet they are also one of the least studied branches in the fungal kingdom. This important discovery opens up a whole new world of prospects in fungal decomposition. Unknown numbers of endophytes exist in the world, many of which may very well hold similar, if not more potent, capabilities.
The curious ability of this “non-saprotrophic” fungus to break down polyester polyurethane encourages us to consider the lineage a given fungal species has descended from, such as those that have become de-lichenized (i.e. fungi whose ancestors were once associated within lichens but are now free-living). Lichens are well-adapted symbiotic colonies of fungal mycelium and algae that grow on plants and rocks. Some contemporary species of free-living (i.e. non-symbiotic fungi) are descended from once-lichenizing fungi and therefore still retain the ability to produce unique chemicals once used to degrade rock and other complex materials by their ancestors. It follows then that these powerful chemicals might also be able to degrade plastics. Some endophytic fungi have descended from lichenizing fungi, as have various mold fungi. Focusing on genera such as Penicillium, Aspergillus, and other lichen-associated fungal species, therefore, may result in a more efficient search for better plastic degraders.
The magic of fungal remediation work, however, is not limited to such trial-and-error approaches to discovering better and better decomposing candidates. In mushroom cultivation there exists the ability to “train” a given fungus to consume an array of food sources that it wouldn’t naturally choose. In remediation work with chemicals, for example, the targeted pollutant is introduced to the fungus at ever increasing concentrations until the fungus has learned to produce the right enzyme at the right amount to be able to survive (and thrive) off this chemical at previously toxic levels. In essence, though the cultivator speaks of “training” the fungus, in reality s/he is only guiding the organism to develop this strength from within itself. It is a sort of dance between the cultivator and the fungus, with each invested in the success of intentional and planned movements together. While this type of “guidance” has yet to be fully developed for endophytes in remediation applications, the potential for training endophytic fungi to consume plastics does exist, as the relatively easy processes used to cultivate them is quite similar to that used with the saprotrophic fungi.
There is a clear need for mycologists to understand and appreciate not only the decomposing abilities of the fungi, but also the environments required to draw them out. The best remediation results will likely arise from following the principles of biomimickry so as to reproduce the degradation processes found in nature. One example of this comes with recognizing the natural succession of decomposers in the wild. When a tree dies, there is a progression of various decomposers that are required to complete the entire breakdown of the plant tissue. Primary, secondary, and tertiary fungi, as well as bacteria are all required to decompose organic matter in the wild. It follows, that for the complete degradation of plastics, a similar progression must be refined and applied for the greatest success. One study in 1978 even tested this theory by using several fungi in succession to degrade poly-epsilon caprolactone with positive results (Kavelman, 1978). Such considerate and non-reductionist approaches that reflect and respect the complexity of nature will likely be the key to begin dealing with the plastics problem.
Throughout the world, psychoactive fungi have long been considered sacred for the insights they provide into the troubles of humanity. The deep sense of interconnectedness and peace these fungi offer was and is an experience seen as a literal teaching; not to be taken lightly, but honored by those willing to put faith in the experience.
In our modern world, such consumption is not available to most people. Instead, new paths toward inner knowledge and a higher understanding of purpose must be gained from external observation of and direct collaboration with the fungi. Even so, the lessons of the fungi and their non-localized mycelial networks readily convey the power had in a life of harmony, respect, and egalitarianism. For here we find that, despite all their evolutionary advantages, fungi still maintain lifecycles that are interdependent on the world around them. Though the fungi could have chosen to dominate their environment long ago, they instead choose to integrate with it, exemplifying the creation of a lifestyle more in balance with the world. This may be the true route of successful evolution. Instead of a “survival of the fittest” model, the fungi demonstrate a “survival of the most symbiotic” as that which survives destruction.
Mushroom cultivators understand that this collaborative approach is necessary for successful harvests. A nurturing process is required in the art of cultivation where the grower supports the fungi to develop its own hidden abilities for confronting and tackling whatever obstacle is presented. In a similar way, we as humans must learn to recognize and develop our own inner talents when confronted with challenges, whether they are personal, interpersonal, or systemic problems such as plastics pollution and environmental destruction. When we enable each other to cultivate these talents in a supportive environment, we find that empowerment naturally arises and the once daunting challenges of the day seem less frightening and are readily overcome. Through the support system of a networked and just community we can, like mycelium, readily communicate solutions to each other as they are discovered, reducing reliance on hierarchical systems that control access to information. Looking to the fungi we can see that many mysteries of the world are still to be explored, and that the end isn’t necessarily in sight, despite the obstacles constantly being presented to us.
We can no longer ignore the plague of plastics on our planet. While reducing needless consumption and increasing recycling efforts lead in the direction of greater awareness, the fact remains that a century’s worth of plastic bottles and packaging will lie buried and leach toxins into the environment for thousands of years to come unless we act now. To successfully tackle the destruction that has already been done new tactics must be developed that go beyond reactionary and point-source models toward more solutions based approaches. Using fungi to directly treat accumulated waste is one such approach that can lead to more holistic avenues for cycling nutrients in the environment.
Caution must be applied, however, to avoid such practices from becoming as easy excuse to continue with a wasteful culture. Without a real reduction in the devastating practices of extraction and manufacturing that lead up to the production of plastic waste, their removal with fungi will only become another “green” way to keep sailing this Titanic in the dark as if nothing could go wrong. Lets us not forget to first Reduce, Reuse, and Recycle. To which should be added a fourth step: Remediate.
When we see that 100 years of study into the plastics/fungi issue has created limited advancement, that funding is increasingly limited for fungal remediation work in general, and that often the powers that be seemingly choose to not invest in real solutions, it might very well come down to the amateur mycologist—or networks of such radical mycologists and microbiologists—to explore these possibilities and come up with solutions together.
The fungal kingdom still holds many lessons for humanity if only it is given the respect and attention it deserves. When the realization is made to change the antagonistic view commonly applied to fungi into one of support and healing, a paradigm shift occurs. The discovery of flaws in such an outdated belief empowers the truth seeker to challenge all other ideologies. In time, new perspectives can arise based on eternal truths, such as the power of harmony over domination in nature. Learning to appreciate the fungi, humans can learn to respect each other and the world more fully. In turn, the normalized ways in which humans destroy the planet become distant memories in the evolutionary process toward symbiosis with nature. In this way, even the polluting of the planet can be seen as hard but necessary lessons on the road toward a more contemplative and intentional way of being. The fungi are there to lend their lessons and to provide their enzymes to help us reduce our impact on the planet they share with us. However we must first come to see them as helpers as such and to cultivate a multi-dimensional relationships with them and the world around us before we can become truly effective.
Fungi can be a key factor in the solution to the plastics problem, but the battle does not end there. Humans can attain the ecological success and longevity of mycelium if we use them as a model for our own communities. The fungi do provide powerful answers; we simply need to learn to ask the right questions.
* This statement is admittedly a bit of an exaggeration. Like any living organism, fungi need carbon and other basic nutrients to grow and survive.
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