A recent discovery has been made which could solve the answer to our growing mountains of plastic waste. With a pile up of 80 million tonnes produced year on year, plastic isn’t going anywhere any time soon, but is nature offering us another helping hand? Formally known as galleria mellonella is the greater wax moth or honeycomb moth which can be discovered across the world. Researchers at Cambridge University in their latest findings found that the larvae of the moths which eat wax in bee hives can also degrade plastic. This surprising breakthrough was first made by an amateur beekeeper frustrated by the wax-eating worms that were feasting their way through her beehive.
"We are planning to implement this finding into a viable way to get rid of plastic waste, working towards a solution to save our oceans, rivers, and all the environment from the unavoidable consequences of plastic accumulation."
When Federica Bertocchini removed an infestation from one of her hives and put them in a plastic bag, the caterpillars simply ate their way out. Upon this discovery, Bertocchini a researcher for the Spanish National Research Council along with scientists at Cambridge University have started studying the behaviour of the centimetre long insects. Lab tests have revealed that 100 worms can demolish 92 milligrams of polyethylene in just twelve hours!
The problem with PET is that while it can be chemically hydrolysed to its monomers, this process can be slow and often requires high temperatures and significant pressure which can cause further damage through process emissions.
Since this discovery, the Spanish National Research Council have patented it for further investigation. It is yet to be identified whether the caterpillars eat their way through the plastic to escape, or to eat it. If the chemical process can be understood then this presents a very exciting prospect for our continuous war with plastic waste.
"We are planning to implement this finding into a viable way to get rid of plastic waste, working towards a solution to save our oceans, rivers, and all the environment from the unavoidable consequences of plastic accumulation," said Dr Bertocchini. "However, we should not feel justified to dump polyethylene deliberately in our environment just because we now know how to bio-degrade it."
Other forms of friendly bacterium:
Oda and Miyamoto's ground-breaking research team screened samples of 250 sediment, soil, wastewater, and activated sludge from a PET bottle recycling facility in Sakai, Japan. After careful analysis of microbial interaction with the waste, they singled out one particularly formidable bacterium that thrived on devouring PET films. The discovered microbe was named ‘Ideonella sakaiensis’ in homage to the city of Sakai where they made the discovery.
Oda and Miyamoto’s group appears to be more efficient than all other previous solutions to the problem of PET deposits sitting inert in landfills. Their microbe carves up polymer at an impressively mild temperature of only 30°C making it a sustainable, biological alternative.
The I. sakaiensis microbe uses a series of enzymes to devour PET deposits. One enzyme, called PETase, breaks the plastics down into the intermediate mono (2-hydroxyethyl) terephthalic acid, or MHET. Another enzyme then hydrolyses the MHET into the monomer’s terephthalic acid and ethylene glycol.
The team of research scientists believe that this enzymatic machinery could one day remediate PET-contaminated environments or reclaim the plastic’s starting material components, which at present are derived from petroleum.
But overall this latest discovery of the plastic-eating caterpillar “will be the starting point," said Dr Bertocchini.
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