About This Project

The massive and rapid accumulation of our plastic and rubber waste is a problem that we cannot afford to ignore. Since certain types of plastic and rubber are held together by the same chemical bonds that are found in natural plant polymers, we are investigating the ability of fungi that live inside plants to degrade synthetic plastics and rubbers.

Ask the Scientists

What is the context of this research?

Research on synthetic polymer biodegradation has been steadily growing over the past forty years. Several bacteria and fungi have been identified that produce enzymes capable of plastic and rubber degradation in various laboratory conditions. However, this field is still in its infancy and much work needs to be done to determine the viability of plastic and rubber biodegradation.

Several plastics and rubbers contain the same chemical bonds that are found in natural plant polymers. Therefore, we are specifically targeting endophytes, organisms that grow symbiotically inside plants, in order to harness the endophytes’ ability to degrade natural plant polymers for the degradation of synthetic plastics and rubbers.

Our group has previously identified degradation of the plastic polyester polyurethane by the endophytic fungus Pestalotiopsis microspora. This fungus secretes a small enzyme that is responsible for plastic degradation. Going forward, our project goals are to:

1) Characterize enzymatic degradation by Pestalotiopsis microspora
- Isolate and characterize enzymatic degradation
- Compare enzyme efficiency to other polyester-degrading enzymes
- Evaluate degradation of solid polyester polyurethane and other plastics
- Evaluate degradation of plastic by P. microspora in simulated landfill conditions (collaboration)

2) Screen for new plastic- and rubber- degrading fungi
- Screen fungi collections for degradation of different synthetic polymers
- For promising candidates, sequence the genomes and look for possible novel plastic- or rubber-degrading genes
- Analyze candidates using gel permeation chromatography (molecular weight changes) and scanning electron microscopy (visual degradation)

What is the significance of this project?

Plastics and rubbers are examples of synthetic (or man-made) polymers that have become an indispensable part of our lives. From our disposable packaging to our grocery bags, from our water bottles to our car tires, we heavily rely on synthetic polymers on a daily basis. These materials are cheap to manufacture, versatile, and resilient -- which also means that they are produced in massive quantities and can last in the environment for hundreds of years. Given that these extremely durable materials are often used for single-use disposable applications, it’s important to think about what happens to plastics and rubbers after disposal.

While we have seen an enormous boom in synthetic polymer production (over 250 million tons of plastic are produced every year!); our methods of treating these materials after disposal have not been able to keep up. Recycling has helped reduce the amount of plastic waste, however only 15% of global plastic is successfully recycled. Additionally, Incineration, another common method of disposal, can form and release toxic chemicals into the environment. Therefore, we are investigating alternative (or complementary) methods of dealing with our plastic and rubber waste.

What are the goals of the project?

All funds raised will directly be applied to furthering the stated project goals of characterizing the biodegradation of plastic by Pestalotiopsis microspora and screening for new plastic- and rubber-degrading enzymes.

A portion of the funds will be used to buy consumable lab supplies, which are necessary for the growth and maintenance of the fungal cultures, enzymatic characterization and materials for additional plastic and rubber screens. I already have access to the necessary equipment for polymer analysis; however, many instruments have fees associated with use and/or several accessory pieces of equipment or consumables need to be bought separately. I will apply the funds towards using equipment such as scanning electron microscopy and gel permeation chromatography.

Additionally, in the Spring I will be going to the Amazon Rainforest as a Teaching Fellow for Professor Scott Strobel's Rainforest Expedition and Laboratory class (all expenses paid; no donated funds will be used for travel). During this time, I will specifically collect fungi that may produce abundant lignocellulolytic enzymes to use in my plastic and rubber degradation screens. If promising candidates arise from these screens, I will use funds to sequence the genomes of the fungi to identify the responsible gene(s) and to synthesize genes that code for putative plastic or rubber degrading enzymes for future studies.