The Potential of Fungi for Cleaning Up Oil Spills

Oil spills are notorious for their devastating impact on the environment, but when traditional methods fall short of fully addressing the long-term damage, how can we effectively remove a substance that is so difficult to break down? Enter fungi: the unsung heroes of environmental restoration. Not only are fungi masters at decomposing organic waste, but they’re also highly effective at dealing with oil pollution.

This process, known as mycoremediation, harnesses the power of fungi to neutralize environmental contaminants, in this case, oil. As researchers become more familiar with the oil-degrading abilities of fungi, we may soon have a more effective and environmentally friendly solution to addressing these challenging spills.

The oil spill dilemma

Every year, thousands of oil spills occur in U.S. waters. These incidents can stem from small-scale events, such as minor spills during boat refueling, but larger spills also happen, especially when oil rigs, refineries, and transportation vessels are damaged. On an annual basis, around 210 million gallons of petroleum end up in the ocean, with another 180 million gallons from natural oil seepage. Additionally, oil spills on land can ruin soil and contaminate groundwater. The estimated oil pollution in the ocean due to land-based runoff is now 20 times higher than it was 20 years ago.

The sheer amount of oil contaminating our land and water has significant environmental impacts. Marine life is particularly vulnerable to the effects of oil spills, as contaminated waters can harm the health of fish, birds, marine mammals, and coral reefs. Oceans and coastal wetlands are crucial environments for biodiversity. Furthermore, land oil spills can negatively affect crops and pollute drinking water sources. We are already seeing the long-term ecological consequences of oil spills. As the world continues to rely on oil to fuel our everyday tasks, these spills will persist unless proper precautionary measures are put in place to prevent further incidents and promote safety within the oil industry. Until then, we need to find the best way to clean up these spills.

Various approaches have been used to address oil spills, but many of these methods can cause additional environmental damage to aquatic ecosystems and air quality. Others are resource-intensive and generate a lot of waste. Mycoremediation may offer a sustainable and effective alternative to traditional oil spill responses, utilizing the unique capabilities of fungi to break down and neutralize oil contaminants.

How can fungi clean up oil spills?

As decomposers, fungi have a root system called mycelium, which they use to degrade organic matter around them into digestible nutrients. This mycelium system is key to remediation efforts. There are two main ways that fungal mycelium can be used for cleaning up oil spills:

1. Enzymatic breakdown

Certain fungal species contain several types of enzymes that can break down the hydrocarbons in oil. These enzymes, secreted by mycelium, degrade the large, complex compounds found in oil and turn them into smaller, less harmful substances. At the same time, the fungi use compounds they’re breaking down as a food source, converting the hydrocarbons into energy and biomass. This dual action of degradation and absorption is what makes fungi particularly effective in bioremediation.

2. Absorption and filtration

Since mycelial threads are so tiny and create a dense network, they can be used to trap the oil within its structure. This extensive mycelial network acts like a sponge, soaking up the oil and containing the pollution within its mass.

Which fungi are best at oil spill remediation?

While many fungi have the ability to break down organic matter, not all species are suited for clearing away oil. Researchers have found that the best candidates for the job are white rot fungi, which excel at degrading complex organic pollutants, such as the hydrocarbons found in crude oil. These fungi produce specialized enzymes that are capable of breaking down the complex molecular structures of lignin. Since hydrocarbons have structural similarities to lignin, they stand no match against hungry wood rot fungi. Some of the most commonly used mushrooms for oil spill remediation include:

Phanerochaete chrysosporium

This fungus is well-studied for its oil remediating capabilities. It is commonly used to create a porous carbon sponge that removes oil and organic solvents (1). 

Oyster mushrooms (Pleurotus ostreatus)

While most people know oyster mushrooms for their delicious taste and hearty texture, these edible mushrooms are also known for their ability to degrade a wide range of pollutants. As a result, oyster mushrooms have been successfully used in various oil remediation projects.

Aspergillus spp.

Some fungi in the Aspergillus species, like Aspergillus niger and Aspergillus flavus have diverse enzymatic profiles, allowing them to degrade hydrocarbons and treat oil-contaminated environments.

Turkey tail (Trametes versicolor)

You may have heard about the medicinal qualities of turkey tail mushrooms, but did you also know that these fabulous fungi are yet another effective ally in oil spill cleanups? Their robust enzymatic activity makes them the perfect fungi for mycoremediation efforts.

Penicillium spp.

Penicillium chrysogenum and other Penicillium species have been found to thrive in heavy oil sludge and are capable of decreasing the total petroleum hydrocarbons in a contaminated area (2).

Mycoremediaiton applications

Renowned mycologist Paul Stamets, who coined the term mycoremediation, has extensively studied the potential of fungi for bioremediation purposes. Inspired to find a solution to some of our most recent, major spills, Stamets and his team developed a strain of oyster mushrooms that is tolerant to saltwater exposure. When this strain is combined with a straw and hemp substrate, it creates floating mats called mycobooms. This innovative method has been found to successfully degrade hydrocarbons in contaminated environments. 

“The oil is absorbed above the water line,” says Stamets. “As the fungi eat the straw, they create CO2, water, acid and enzymes, and the fragrances of mycelium attract insects and fish. There is a whole domino effect of benefits. Mycobooms would keep new oil out on the outside, while on the inside they would release enzymes to remediate the oil already in the marshlands habitat.”

Stamets has since submitted proposals for Mycobooms to be used to clean up larger oil disasters, like the Gulf War and Deepwater Horizon oil spills.

In another one of Stamets’ tests,  researchers inoculated contaminated soil with oyster mushrooms to remediate oil pollution. Over a period of 16 weeks, the hydrocarbon concentrations in the soil were reduced from a highly toxic level of 10,000 ppm to just 200 ppm. This significant reduction in toxicity allowed the cleaned soil to be approved by regulators for use in landscaping along highways.

Although it’s not likely that we’ll be using fungi as a primary means of addressing oil spill pollution any time soon, it still stands as a promising future technology once researchers can better understand how to use it on a larger scale. The success of Mycobooms and similar research initiatives demonstrate the potential for integrating mycoremediation into larger environmental cleanup strategies. Further research and development efforts could refine these techniques to enhance their efficiency and scalability. 

Future directions

Mycoremediation offers several exciting opportunities to enhance environmental cleanup efforts. Beyond oil remediation, fungi have also shown potential in removing environmental toxins and degrading plastic that would otherwise sit in our landfills for decades. Ongoing innovations in this field may eventually enable us to fully leverage the capabilities of fungi for environmental restoration, providing a sustainable tool in our battle against pollution and ecological decline.

References

1. Gong, Yue, Lejie Pan, Huahui Yuan, Juncheng Li, Xin Li, Qian Chen, Yue Yuan, Xian Wu, and Sheng-Tao Yang. 2023. “Porous Carbon Sponge from White-Rot Fungus Phanerochaete Chrysosporium for the Removal of Oils and Organic Solvents.” Materials (Basel, Switzerland) 16 (2): 534. https://doi.org/10.3390/ma16020534.

2. Yang, Shaoqi, Junhui Zhang, Yue Liu, and Wendi Feng. 2023. “Biodegradation of Hydrocarbons by Purpureocillium Lilacinum and Penicillium Chrysogenum from Heavy Oil Sludge and Their Potential for Bioremediation of Contaminated Soils.” International Biodeterioration & Biodegradation 178 (March): 105566. https://doi.org/10.1016/j.ibiod.2023.105566.