A living plastic with a pair of cooperative, plastic-busting enzymes degraded the material completely within six days. Adapted from ACS Applied Polymer Materials 2026, DOI: 10.1021/acsapm.5c04611
There cannot be a truly sustainable earth if excess plastic products abound. Traditional plastics persist for centuries and result in toxic microplastics.
Researchers in China are seeking to address this problem by creating products that self-destruct on command, known as “living plastics.” These materials incorporate activatable, plastic-degrading microbes alongside the polymers.
While previous attempts relied primarily on a single enzyme, this team wanted to improve the destruction efficiency. So, they engineered Bacillus subtilis to produce two cooperative, polymer-degrading enzymes. One enzyme acts as a random chopper, snipping the long polymer chains into smaller pieces, while the other slowly chews these pieces into their monomer building units from each end.
The team mixed the dormant spore form of B. subtilis with polycaprolactone (a polymer common in 3D printing and some surgical sutures) to protect the microbes before they were needed. The resulting living plastic had mechanical properties similar to those of plain polycaprolactone films. However, once a nutrient broth at 122 F was added, the spores activated, breaking the plastic all the way down to its base building blocks after just six days. The cooperation between the enzymes was so efficient, it even prevented microplastic particles from being created during the degradation process.
As a proof-of-concept, the researchers created a wearable plastic electrode out of their living plastic and found it performed as expected, degrading completely within two weeks.
In future work, the team hopes to develop a trigger for the spores in water, where a large portion of plastic pollution ends up. Though this work focused on just one polymer, a similar strategy could be used in other plastic types, including those commonly found in single-use plastics.
Data from American Chemical Society