A worm that eats plastic, a recent discovery that could be a game changer for preserving the environment from the pollution of this now abundant and toxic material. This now ubiquitous material is found in seas, soil, fish and we are even finding microplastics inside of us.
But the larvae of the Zophobas Morio can eat and digest polystyrene in just a few days — the main polymer used to make plastic — which normally takes decades to break down naturally.
Scientists at the School of Chemistry and Molecular Biosciences of the University of Queensland in Australia started the research in 2017. In the experiment, the researchers divided the worms into three groups and the small larvae were fed different foods. The first group were fed wheat, the second polystyrene, and the third were given nothing. The results were published in the scientific journal Microbial Genomics.
The results are that the worm eating the polystyrene grew more than the others, proving the worm can take energy from polystyrene thanks to the microbes that are inside them.
The discovery is exceptional and new studies will now start to understand how to exploit it. It is impossible to think of feeding all the plastic to millions of larvae. It is necessary instead to understand what is the process of degradation of polystyrene and to isolate substances that allow rapid decomposition. We can then use the system to get rid of a problem that poses a serious risk to the health of the planet.
The “super worm” has been proposed, in several nutritional studies, as an alternative food, for its high content of proteins and fats. But he has also been known for his “superpower” of eating polystyrene. This was first noticed a few years ago by a group of Filipino high school students. Since then, this ability of the Zophobas Morio (its scientific name) has become a matter of study.
Chris Rinke and researchers from the Australian University’s School of Chemistry and Molecular Biosciences have put this talent to the test. The life cycle of the larvae of Zophobas Morio, like all larvae, predicts that at some point they form a cocoon, become pupae, and resurface as an adult individual. In their case, a black beetle. This happens if they remain isolated. But if raised in large groups, larvae remain and continue to eat.
According to the results, presented in a paper published in the journal Microbial Genomics, “the super worms that fed on polystyrene not only survived but also took a bit of weight — says the team coordinator — this means that worms can draw energy from polystyrene, more likely with the help of microbes inside them”.
The researchers used a technique called metagenomics to find different enzymes inside the larvae that have the ability to degrade polystyrene and styrene. Although recent studies suggests polystyrene degrades in over hundred years in sunlight, the larvae can engage in the same process in just a few days.
Instead of filling giant tanks with millions of super worms that open their jaws waiting for a cascade of white polystyrene (fascinating idea but impractical), there are other possibilities, like chopping the material and then feeding it to the enzymes replicated thanks to the study. We could also grow the larvae’s intestinal bacteria in a laboratory and further test their ability to degrade polystyrene and “increase this process to a level required for an entire recycling plant,” said Jiarui Sun, a PhD student working on the project. According to Rinke “the degradation products of this reaction can be used by other microbes to create high-value compounds such as bioplastics”.
Zophobas Morio is just one of the invertebrates that promise to help mitigate the problem of the billions of tons of plastic that are produced each year and dispersed in the environment around the world. The Tenebrio Molitor also has these abilities. In 2017 an Italian biologist (and beekeeper) Federica Bertocchini, from the Spanish Institute of Biomedicine and Biotechnology of Cantabria, discovered this caterpillar that eats polyethylene. It is the larva of the Galleria mellonella, called the “wax moth”.
All over the world, research institutes and companies are studying enzymes derived from insects and microorganisms found in compost and landfills that have the “superpower” of degrading plastic. We don’t know if this could be the turning point for the future, but after the damage we have done to our planet, it makes sense that the solutions to our current crises exist in the natural world.