Getting rid of used plastic has been on the top of many researchers’ dreams for quite some time now. Huge rafts of plastic circulating in the oceans, local dumps full of the stuff and the seemingly ever-increasing numbers of plastic containers on supermarket shelves have made all of us aware of how dangerous this wonderful invention actually is. Historically, most man-made products tend to degrade in a reasonable amount of time, even ourselves, but plastic doesn’t. What was once considered a wonder of technological invention, which it was, has now been recognized, hopefully not too late, as a threat to our planet’s survival, let alone our own.
This blog is about several efforts that show promise for getting rid of used plastics in an ecologically-friendly way. One can only hope their promise turns out to be realized.
The first report is from a group of University of Queensland scientists. These Australian researchers have found the Zophobas morio – commonly known as a super-worm – can survive on a diet of polystyrene. They believe these beetle larvae digest the plastic through a gut enzyme.
“Super-worms are like mini recycling plants, shredding the polystyrene with their mouths and then feeding it to the bacteria in their gut,” Dr. Chris Rinke said. An interesting was of getting rid of used plastics.
The University of Queensland team fed three groups of super-worms different diets over three weeks. The batch that ate polystyrene even put on weight. The team found several enzymes in the super-worm’s gut have the ability to degrade polystyrene and styrene: Both of these products are common in takeaway containers and other items such as insulation and car parts.
The research is unlikely to lead to massive worm farms that double as recycling plants. That line of development, as well as being inefficient, could well lead to a massive worm problem that might be more difficult to eliminate than plastic. Science is full of examples where the “cure” turns out to be worse than the original problem. We have to be careful that getting rid of plastics isn’t one of those cases.
The scientists hope to identify which enzyme is the most effective, so it can be reproduced at scale for recycling. However, there is always the question whether such techniques will ever be commercially viable but the creation of mountains, and islands, of plastic waste dictate we must keep trying until a viable solution is found, hopefully soon.
Similar work at the Biological Research Center in Madrid resulted from Dr. Federica Bertocchini noticing that, when she cleaned her beehives of wax worms and placed them in plastic bags, lots of holes began to appear in those bags. “We found that the wax worms were not only chewing the plastic but also digesting it,” she said. The scientists said it might one day be possible to have kits of wax worm enzymes in homes to recycle plastic bags into useful products.
A super-enzyme that quickly breaks down plastic drink bottles, usually made from PET plastic, was revealed in 2020, inspired by a bug found in a waste dump in Japan and accidentally tweaked to increase its potency. An enzyme that breaks down PET has also been produced from bacteria in leaf compost, while another bug from a waste dump can eat polyurethane, a plastic that is widely used but rarely recycled. All sorts of interesting ways of getting rid of plastics.
Still another approach comes from a research group at the University of California-Berkeley, who are working to “undo” the chemical process that creates non-degradable plastics. In other words, they are trying to physically disassemble plastic to make something that is easier to recycle or destroy. A little more complicated than using plastic-eating worms but apparently feasible.
In simple terms, plastics are created by combining monomers (single molecules) into long chains of the same molecules: It’s rather like creating a “daisy-chain”. Reversing that process to go back to single daisies is an analogy of what the Berkeley scientists are trying to do. It remains to be seen whether it will work, for how many types of plastics it will work, and how the resulting individual “daisies” can be eliminated in an ecologically-friendly way.
I am sure these are just a few of the ways that scientists are attacking the issue of the world slowly drowning in used plastic, but it’s encouraging to know that many different approaches are being tested. Human ingenuity will find a solution. The issue is when, and how much of our world will be contaminated by the time that happens.