Oyster Mushroom Breakdown of Microplastics

ISEF Category: Microbiology

Subcategory: Applied Microbiology  ·  Difficulty: Intermediate  ·  Setup: School Lab  ·  Time: 1 to 2 Months

The Hook

Tiny plastic pieces are now found in water, soil, and even food webs. That makes them a real cleanup problem, not just a trash problem. Oyster mushrooms make enzymes that break down tough organic material, so a lot of students ask if they can also change plastic surfaces. Your job is to test that idea with measurements you can defend.

What Is It?

Mycoremediation means using fungi to help clean up pollution. Fungi grow as thread-like cells called hyphae. Those threads spread through a material and release enzymes, which are proteins that speed up chemical reactions. In this project, you are asking whether oyster mushroom mycelium can alter microplastics, especially polyethylene and polystyrene chips.

Think of the fungus like a slow, living network that presses against a plastic surface. If the plastic changes, you may see less mass, more surface pitting, or small shifts in infrared spectra. Infrared spectroscopy, or FT-IR, measures how a material absorbs light at different wavelengths, which can hint at chemical changes on the surface. You do not need to prove that the fungus fully decomposes plastic. A strong project can test whether the surface changes at all, and whether those changes differ by plastic type.

Why This Is a Good Topic

This topic works well because you can turn a big environmental question into measurable parts. You can compare treated and untreated chips, track mass, inspect surfaces, and analyze spectra. It connects to plastic pollution, fungal biology, and materials change in a real-world setting. You can learn how to set controls, collect repeatable data, and decide whether a signal is real or just noise.

Research Questions

• How does oyster mushroom colonization affect the mass of polyethylene chips compared with untreated chips?
• How does oyster mushroom colonization affect the mass of polystyrene chips compared with untreated chips?
• What is the effect of exposure time on surface pitting scores in polyethylene chips colonized by oyster mushroom mycelium?
• What is the effect of exposure time on surface pitting scores in polystyrene chips colonized by oyster mushroom mycelium?
• Does the carbonyl index proxy from FT-IR change more in treated microplastics than in controls?
• Which plastic type shows greater surface change after colonization by oyster mushroom mycelium?

Basic Materials

• Oyster mushroom home-grow kit or spawn from a reputable supplier.
• Clean polyethylene and polystyrene chips or pellets of known type.
• Small digital kitchen scale with 0.01 g or better resolution.
• USB microscope or handheld digital microscope.
• Petri dishes, sterile plastic containers, or zip-top bags for separate treatment groups.
• Nitrile gloves and lab coat or apron.
• Forceps or clean tweezers.
• Distilled water.
• Labels and waterproof marker.
• Ruler or calibration slide for microscope scale.
• Notebook or spreadsheet for data logging.

Advanced Materials

• School access to FT-IR or ATR-FTIR instrument.
• Analytical balance with 0.001 g resolution.
• Stereo microscope for surface inspection before imaging.
• Image calibration target or stage micrometer.
• Incubator or controlled temperature space for fungal growth.
• Autoclave or pressure sterilization setup for materials that need it.
• Reference plastic standards for polyethylene and polystyrene.
• Software for spectral baseline correction and peak ratio analysis.
• Optional scanning electron microscope for higher-resolution surface imaging.

Software & Tools

• ImageJ: Measures pit area, surface roughness proxies, and image contrast from microscope photos.
• Excel: Organizes treatment groups, calculates averages, and makes basic graphs.
• Google Sheets: Lets you log data from multiple trials and share it with teammates or mentors.
• R: Supports statistical tests, plots, and cleaner data analysis for multiple plastic types.
• FTIR spectral software: Helps compare treated and control spectra, then estimate a carbonyl index proxy.

Experiment Steps

1. Define the plastic type, fungal strain, and outcome measures you will compare first.
2. Set up treated and untreated groups so you can tell fungal effects from storage or moisture effects.
3. Decide how you will standardize chip size, image scale, and starting mass before exposure.
4. Plan a repeatable imaging workflow so surface pitting scores come from the same view rules each time.
5. Build a spectra comparison plan that uses the same peak ratio or proxy across all samples.
6. Choose the statistics you will use to compare groups and decide what counts as a meaningful change.

Common Pitfalls

• Mixing chip sizes or plastic grades, which makes any mass change hard to interpret.
• Letting moisture stay on samples before weighing, which can hide or fake mass loss.
• Using microscope photos from different angles or lighting, which changes the apparent pitting score.
• Comparing spectra from different instrument settings or baseline corrections, which can create false carbonyl shifts.
• Forgetting a no-fungus control, which leaves you unable to separate fungal activity from normal aging.

What Makes This Competitive

A strong version of this project goes past a simple before-and-after claim. You can compare at least two plastic types, track multiple endpoints, and use matched controls with enough repeats to support stats. A better entry also explains the limits of each metric, like why mass loss alone can miss surface change. If you can connect microscopy, spectra, and a clear experimental design, your project will look much more serious.

Project Variations

• Test whether oyster mushroom changes polyethylene film, rigid pellets, or foam pieces more strongly.
• Compare oyster mushroom with another edible fungus, such as shiitake or turkey tail, using the same plastic chips.
• Add a treatment that varies nutrient conditions so you can ask whether the fungus changes plastic more when it has less food.

Learn More

• USGS microplastics resources: Search the U.S. Geological Survey site for background on microplastics in water, soil, and wildlife.
• NOAA marine debris and microplastics: Search NOAA resources for plain-language background on plastic pollution and monitoring.
• PubMed: Search for review articles on fungi, microplastics, and biodegradation to find current research.
• NIH PubChem: Look up polyethylene and polystyrene to review polymer structures and related properties.
• MIT OpenCourseWare spectroscopy materials: Search MIT OpenCourseWare for intro spectroscopy lectures that explain FT-IR basics.
• Applied and Environmental Microbiology: Search this journal for studies on fungal degradation and environmental microbiology methods.