Yale Undergrads Find Plastic-Eating Fungus

The growing garbage problem may have a new solution–fungus that eats plastic. For years mounting mounds of plastic have been choking landfills and polluting the ocean. Now an annual undergraduate trip to the rain forest may have found a solution to the plastic problem.

Unleashing creativity in science sometimes has amazing results. That’s what a group of Yale students discovered after they took a trip to the Amazon rainforest in search of fungus that could hold medical or scientific promise. Upon their return they tested the fungus to see if they could detect any biological activity.

One undergrad started the project in 2010 and then graduated. Another 2011 participant in the Yale Rainforest Expedition and Laboratory course picked up where she left off and that led to the isolation and discovery of an enzyme in a fungus that helps degrade polyurethane and turns it back into carbon.

Dr. Scott Strobel says, “The average third grader asks all kinds of great questions; they probe, poke and manipulate. Then somewhere around fourth grade we drive the interest in science right out of these kids. People conclude they can’t do science, but in reality they have been doing science all their lives.”

He teamed up with Howard Hughes Medical Institute to create the class and create opportunities for students to apply what they learn in the classroom to the real world. HHMI gave a $1 million grant to fund the program for four years.

Yale biochemist Kaury Kucera is a post doctorate researcher who co-leads the annual rainforest trek. She told the New Haven Register, “We take 15 undergraduates into the Ecuadorean rain forest and collect plant samples.”

Each year, students collect organisms called endophytes found in rainforest plants and then take them back to New Haven to test them for biological activity. The whole program is student-generated so they decide what they want to study. Once back in the lab, students analyze the endophytes that show biological activity to see whether they might have any medical or other practical use.

In 2008 Pria Anand was part of the trip to Ecuador where she gathered plants and later extracted part of a fungus to test its affect on plastic. Her goal was to help reduce the piles that are swelling in landfills, also known as bioremediation. She graduated in 2010 before getting the results she wanted.

Jeffrey Huang in the same class was studying which endophytes were most effective at breaking down chemical bonds.

This year, Jonathan Russell tested one of Huang’s best endophytes on Anand’s bioremdiation task. From there Russell focused on locating the enzyme in the fungus that is most effective on breaking down plastic.

All three undergrads are listed as lead authors on the forthcoming paper Biodegradation of Polyester Polyurethane by Endophytic Fungi in the journal Applied and Environmental Microbiology.

This is not the first time a particular agent has broken down polyurethane. But this enzyme can operate in an oxygen-free zone, such as those found underground in landfills.

Since the discovery students in another class are looking at different endophytes to see which if any will be most effective at dissolving polystyrene or styrofoam, one substance that is designed to stick around indefinitely.

Two different Yale students in the 2009 Rainforest Expedition class have had other fungal breakthroughs which could lead to a new “myco-diesel” biofuel and another which could protect agricultural farms from pathogens.

Breaking Down the Degradation of Common Items in Landfills

Dungeness Spit Composition Timeline

Decomposition Timeline, from Dungeness National Wildlife Refuge, WA, photo by: Hadley Maris

Piece of paper — 2-4 months
Orange peel — 6 months
Waxed paper cup — 5 years
Disposable diaper — 10-20 years
Leather shoe — 25-40 years
Nylon fabric — 30-40 years
Tennis shoe sole — 50-80 years
Tin can — 80-100 years
Aluminum can — 200-400 years
Six-pack ring — 450 years
Glass bottle — 1 million years
Fishing line — *Indefinite
Plastic bottle — *Indefinite
Styrofoam cup — *Indefinite

*Undergraduates at Yale are working to find enzymes in rainforest fungus to reduce the decomposition timeline

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