SCI FACTS'25 - Plastic Eaters

A bacterium discovered at a recycling plant in Japan, Ideonella sakaiensis, has evolved to "eat" PET plastic—the same material used in most water bottles—converting it into energy and harmless organic compounds.

Nature’s Newest Evolution

For decades, PET (polyethylene terephthalate) was considered non-biodegradable, taking centuries to break down. However, in 2016, scientists isolated Ideonella sakaiensis, a microbe that evolved the rare ability to thrive on a diet of synthetic plastic.

The Enzymatic "Super-Duo"

This bacterium utilizes a highly specialized two-step process to dismantle plastic at the molecular level:

• PETase: This first enzyme attaches to the plastic surface and breaks the long polymer chains into smaller fragments called MHET.
• MHETase: A second enzyme then steps in to further digest these fragments into two harmless building blocks: ethylene glycol and terephthalic acid.

The "Super-Enzyme" Breakthrough

While the natural process is slow—taking weeks to degrade a thin film—scientists have successfully engineered a "super-enzyme" by fusing PETase and MHETase together. This lab-enhanced version works six times faster and can even handle highly crystalline "hard" plastics found in commercial bottles.

A Solution for the Plastic Crisis

This discovery is paving the way for a circular plastic economy. Instead of plastic ending up in landfills or oceans, it can be:

• Biologically Recycled: Broken down into pure monomers to create new, high-quality plastic without using more crude oil.
• Large-Scale Remediation: Used in industrial waste facilities to safely degrade mountains of plastic waste.
• Environmental Cleanup: Potentially adapted to clear microplastics from soil and water systems.