Polyurethane is everywhere — in couch cushions, running shoes, refrigerator insulation and even the foam beneath carpet. It is one of the most widely used, yet least recyclable plastics on Earth. Designed to last for centuries, it’s now contributing to the plastic waste problem. However, this soil fungus found living in a landfill in Islamabad, Pakistan, can break down polyurethane in weeks. Nature may provide a solution to the material waste problem that humans invented only decades ago. 

How the Aspergillus Tubingensis Fungus Eats Plastic

Aspergillus tubingensis is a naturally occurring soil fungus that grows on the surface of plastic. It secretes enzymes that break the chemical bonds between plastic molecules, and uses the physical strength of its mycelia — the root-like filaments fungi grow — to physically pull the plastic apart. It works in three stages: the spores attach to the plastic surface, the fungus spreads across it, then the enzymes go to work dissolving the bonds that make polyurethane so durable and so persistent.

In laboratory conditions, complete degradation occurred in liquid medium after two months, with 90% degradation observed in weeks, not decades.

It does not need special conditions, a laboratory or human engineering to break down the plastic. The fungus evolved this capability on its own, possibly as a result of living among the waste humans left behind.

Why Polyurethane Is Such a Problem

Most plastics are difficult to recycle; polyurethane is one of the most challenging. Unlike other plastics, it cannot be melted down and remolded as it resists chemical breakdown. It can persist in landfills nearly indefinitely. It is used in furniture, footwear, insulation, fake leather, medical devices and dozens of industrial applications, many of which have no set system for regeneration.

What Makes This Fungus Different From Other Plastic-Degrading Organisms

To date, 436 species of fungi and bacteria have been found capable of degrading plastic. Most work slowly, require specific conditions or target only certain plastic types. Aspergillus tubingensis can uniquely target polyurethane with a quick degradation process, unlike other fungi.

Complications in Using Aspergillus Tubingensis at Industrial Scale

While the fungus is promising, it performs differently depending on temperature, pH and environment. Researchers in the growing field of mycoremediation — the use of fungi to clean up environmental waste — are actively working to scale the technology for waste treatment plants and contaminated land sites around the world.