Mushrooms Break Down Oil and Plastic In Bioremediation

Imagine taking a walk through the forest. It's a dimly lit, overcast day, and the ground is moist from days of raining. As you walk underneath the canopy, you spot something interesting on the ground. It's not a plant, and it's not an animal, but the brightly colored cap of a freshly sprouted mushroom. Most people's first instinct would be, "better stay back, it could be toxic." But if you happened to have a mycologist with you, you might realize that mushrooms like this are being explored on the cutting edge of bioremediation - being used to break down previously harmful materials like oil and plastic.

Most people aren't aware of what goes on underneath the surface when they find a mushroom. Mushrooms aren't like plants, a single mushroom does not constitute an entire organism. In fact, the mushroom itself is not even the body of the organism, it is the fruit. Like a strawberry or a watermelon, the mushroom merely carries the seeds (spores) that will disseminate out into the environment. The real organism is buried beneath the soil, comprised of a vast branching network of cells known as the mycelial network.

This mycelium is what decomposes organic compounds, returning nutrients to the soil and releasing CO2 for plants to breathe. As the mycelium (a single thread is known as a hyphae) spreads outward, it releases enzymes that break down long polymer chains into their basic subunits, such as sugars. These smaller molecules can then be absorbed through the hyphal walls. The interconnectedness of the mycelial network allows for both rapid break down of organics in soil, and also swift distribution of nutrients throughout the network. Mycelial colonies are extremely resistant to other micro-organisms, as well as physical damage. No particular area of the network is vital to another area, so if a section gets damaged, the network either sacrifices it, or works quickly to repair it. There is also no limit to how large these networks can grow. In fact, one of the largest organisms in the world is an underground mycelial mat spanning 2,400 acres (or 1665 football fields) in a forest of eastern Oregon. The mat is believed to be over 2,200 years old and a small sample is shown in a micrograph below. 

The real magic of mushrooms and their mycelial networks are quickly being discovered. Mycologist Paul Stamets has been driving the field to new discoveries in bioremediation and antibiotics. The ability of mycelium to produce enzymes that break down long chains of hydrocarbons is unique. No other organism is as efficient at producing and distributing these enzymes than is mycelium. In fact, it is so efficient that a mycelial colony is capable of restoring soil saturated with oil and other hydrocarbons that are toxic to life-bearing condition.

In an experiment where bioremediation groups were tasked with reducing a pile of contaminated soil to a reusable state, Paul Stamets discovered a special strain of oyster mushroom that is highly efficient at breaking down the PAHs (polycyclic aromatic hydrocarbons) found in oil and petroleum. It took merely four weeks for the mycelium to build its network, and overtake the contaminated soil. Large oyster mushrooms grew straight out of the dirt, some of the caps reaching sizes of 12 inches in diameter! This massive explosion of mushroom fruit bodies attracted innumerable amounts of flies and insects that could call the mound of dirt "home", and the previously contaminated soil became its own habitat. The coming of insects brought birds, the birds brought plant seeds, which were allowed to sprout and flourish after the mycelium had detoxified the soil and provided essential nutrients for grass to grow.

This breakthrough in myco-technology has many beneficial ramifications should they be pursued. Managing fossil fuel waste has been a huge topic of the environmental industry in recent years. Companies that burn fossil fuels stockpile waste until it has to be moved to another location, or buried in the ground, causing further contamination risks. Most fossil fuel wastes contain a significant amount of PAHs, a prime source of energy for mycelium. Mushrooms could be used to significantly decrease the toxicity of this waste by inoculating them with the proper mushroom strain. While this would still leave mineral contaminants such as arsenic, barium, and manganese, many of the PAH carcinogens could be removed by mycelium. In the search for sustainable energy and biomass fuels it is important to remember what can be done to reduce the impact of current fuels on our environment, bioremediation is one alternative making a lot of headway.

In addition, many companies are beginning to utilize biodegradable plastics derived from corn starch and sugarcane. Biota bottled spring water is one great example of this. Their water bottles are made completely from corn which is fully compostable. For all compostable products mushroom mycelium is a great aid in the breakdown process. Not only does it catalyze the composting of these plastics, it can promote healthy soil at the composting sites, and produce mushrooms fruits that could be used for medicinal and culinary applications. In many dense city areas, it is quite difficult to find a region in which plastics biodegrade quickly. By introducing mushroom mycelium, the compost sites could be placed virtually anywhere, even indoors or underground, as mycelium does not require light to grow.

Other provocative discoveries by Stamets include a new type of biofiltration process known as mycofiltration, a fungal strain capable of wiping out termite and carpenter ant colonies, and strains that produce metabolites effective against human pathogens such as pox and flu viruses. Some of these strains grow naturally in old growth forests around the US, and Stamets has been able to get approval from the US Department of Defense to declare these forests national protected land areas as a matter of national defense.

While the mushroom may seem to be a bit mysterious, there appears to be at least one man asking the right question. What can this beautiful organism do for us? Be sure to tune in again for another way mushrooms can restore our planet Earth here at biomass authority!

References

Fungi Perfecti. Retrieved Feb. 14, 2009, from
www.fungi.com/mycotech

Stamets, Paul (2003). Mushroom Power. Retrieved Feb. 14 2009, from
http://www.futurenet.org/article.asp?id=597