As consumers demand sustainable alternatives to single-use plastics, compostable plastic items have become increasingly popular in recent years. The problem, however, is that many of these ‘compostable’ items don’t break down in regular composting conditions and tend to contaminate other recyclable plastics. This means that a large part of compostable plastic ends up in landfills, where they can take centuries to biodegrade.
In an effort to solve this problem, a team of researchers from the University of California, Berkeley, has come up with a way to break down compostable plastic in just a few weeks with just heat and water inputs.
“People are now prepared to move into biodegradable polymers for single-use plastics, but if it turns out that it creates more problems than it’s worth, then the policy might revert back,” said study lead Ting Xu, a UC Berkeley Professor. “We are basically saying that we are on the right track. We can solve this continuing problem of single-use plastics not being biodegradable.”
The new process involves adding polyester-munching enzymes to the plastic during production. These enzymes are then covered with a simple polymer wrapping to protect them from untangling and becoming useless. When the plastic is exposed to heat and water, the enzymes get rid of this protective coating and start breaking down the plastic into its building blocks. Essentially, the enzymes catalyze a process of self-destruction in the plastic.
This programmed degradation, according to Xu, could be key to preventing a great variety of plastic items from polluting the environment: “Imagine using biodegradable glue to assemble computer circuits or even entire phones or electronics, then, when you’re done with them, dissolving the glue so that the devices fall apart and all the pieces can be reused.”