Styrofoam plastic waste and superworms by Australian researchers
Humans have created lots of artificial things. None are as problematic as plastics including PFAS. Styrofoam is one those light plastics which does not decompose quickly at all.
For a long time scientists have endeavoured to find better was and means of recycling such plastic and synthetics. So it seems that the lowly earthworm might be part of the next innovative solution.
Researchers from Australian University of Queensland have made a discovery that claims beetle larvae form, can eliminate traces of styrofoam from our environment.
https://www.sciencealert.com/styrofoam-munching-superworms-could-lead-to-plastic-upcycling/amp
Styrofoam, commonly known as polystyrene(PS) is a common plastic found in everyday packaging which accounts for around 10% of all non fibrous products made.
This common packaging is very useful in shopping fragile parcels because ti has the ability to absorb shocks caused by accidentally dropped packages.
Polystyrene is not easy to process at all, and not recyclable in common household bins. The beetle is the potential candidate to help break down such plastic waste.
The larvae of the beetle is more commonly known as a super worm. It’s the prey of most insectivorous animals, but it’s not just a tasty snack, its gut or stomach has a certain makeup of enzymes which seem to be incredibly effective at dissolving plastic.
Apparently the super worm can live off of a diet of polystyrene alone, and even become bigger and fatter in the process.
Wax worm, Indian mealworm, rice mealworm, mealworm
It’s also been discovered that wax worms mealworm, Indian mealworm, rice mealworm and mealworm are another of nature’s wonderful insects that can ingest plastic, giving scientists another avenue to explore in combating non biodegradable plastic waste.
https://www.nature.com/articles/s41467-022-33127-w
Indian mealworms’ larvae has certain microorganisms in their gut, that can break down the plastic. After digestion, only water-soluble products are left. Rice mealworm eats low density polyethylene.
Meal worms eat polyethylene, polystyrene, polypropylene and polyvinyl chloride(PVC). They are also able to digest four types of plastic because of bacteria and enzymes in their gut.
With almost 300 million tons of plastic being manufactured every year of which the majority is non biodegradable and a big risk to the earth’s ecosystem.
Polyethylene(PE) accounts for 30% of synthetic plastic production, largely contributing to plastic waste pollution on the planet to date. Principal uses are in packaging film, trash and grocery bags, wire and cable insulation, squeeze bottles, toys and housewares.
There are two types of polyethylene. One is low density polyethylene, the other is high density version.
The search is on to find solutions. Who would have considered that common insects would be capable of chewing their way through a plastic bag? Federica Bertocchini, a biologist from University of Cantabria discovered that they can.
These wax worms are the larval form of small months, and they commonly live on a diet of was from inside the hives of bees. Plastic is actually very similar to wax. Wax worm’s saliva and enzymes are key polyethylene(PE) degradation.
And both are polymers meaning that they are made up of a long string of carbon atoms bound together with other atoms branching off to the sides, and they both share a similar carbon backbone.
Beeswax and polyethylene have structural similarities. Wax worm’s salivary first transforms the polyethylene into other materials, which then later can be degraded by microorganisms in their gut.
It’s possible that the worms could have evolved a molecule to break down wax, and in turn that seems to also work on plastic. Study author Chris Rinke explained that the worms act as mini recycling plants, shredding the plastic and absorbing in their guts where the enzyme can break it down.
Meta genomics, saliva and enzymes for use in a proper recycling plant
Above Australian team used a technique meta genomics to analyse the microbial gut community and find which gene encoded enzymes were involved in degrading the plastic.
Rinke team used a process called meta genomics to isolate the microbial genes that are responsible for the whole process. In tests, overnight 100 wax worms had degraded approximately 92 milligrams of a plastic shopping bag.
The rate of ingestion is painfully slow however, and at that rate it would seem to take those same 100 worms over 30 days to completely break down a 5 gram plastic bag.
So in the end it seems that it’s not practical to expect beetle larvae to pick up all the slack when it comes to breaking down unwanted plastic waste in our environment.
To decompose the plastic, not only microorganisms in the gut are at work, but also enzymes that are produced by the gut. Enzymes are protein substances in a body that speed up chemical reactions, without being changed by these reactions.
But through enzyme engineering, we could engineer and manufacture enough of the enzymes for use in a proper recycling plant, and the results would be much more realistic.
The breakdown products from that reaction could then be fed to other microbes to create high value compounds, such as bioplastics, in which Rinke hopes would become an economically viable upcycling approach.
Despite all this in the grand scheme of things the ultimate solution to solving plastic pollution is to simply make less of it, and recycle the types that we have manufactured already.
Source: nature, medium, sciencealert
