- Kathryn Patterson
Plastics vs Nature? Nature FTW!
G. mellonella larva
Plastic waste is an environmental nightmare. It's found everywhere: from the side of the road to the snow in arctic regions. And the big question is, "how do we get rid of it?"
Burning plastics releases microplastics into the atmosphere. Putting plastics in landfills leads to a decades-long degradation process that releases microplastics into the ground and groundwater. Dumping plastics into water (a river or the ocean) breaks down into microplastics that end up in the food chain, and ultimately in humans. We humans have yet to find a way to dispose of plastic that doesn't just end up becoming more of a problem.
Nature to the Rescue!
Yes, folks, nature has been busy creating ways to deal with this seemingly impossible problem. Scientists have a new category of creatures - plastivores - who can eat and digest plastics.
In 2016, Japanese scientists discovered Ideonella sakaiensis, a bacteria that eats through polyethylene terephthalate (PET). (The type of plastic is found in 20 oz. bottles.) This bacteria contains two different enzymes that break down the long polymer chains in PET.
This discovery, while amazing on its own, lead to more research on how to use this bacteria to help with plastic pollution. Two different groups advanced the use I. sakaiensis:
The University of Portsmouth researchers took this bacteria and created a cocktail that breaks down plastics around six times faster than I. sakaiensis alone.
In the University of Edinburgh, researchers modified E. coli to include I. sakaiensis, allowing E. coli to not only break down plastics, but to create a synthetic vanillin out of said plastics. This turns waste plastic into artificial vanilla extract, solving two problems at once.
In 2017, European scientist and amateur beekeeper Federica Bertocchini discovered that the saliva of wax worms contains two different enzymes that also break down plastic polymer chains. Wax worms are the larval form of the greater wax moth, Galleria mellonella. Bertocchini made her discovery while removing wax worms from her bee hives.
Basically, these enzymes break down polyethylene (PE), a type of plastic that accounts for 30% of synthetic plastic production and a large percent of the plastic waste pollution. It's contribution to pollution is based on the fact that PE is one of the most resistant polymers.
So these enzymes not only work on a heretofore hard to dispose of polymer, but they also work at regular temperatures and regular pressure.
Every day, scientists discover more ways that nature has created to help us get rid of and possibly recycle plastic waste. They have found tens of thousands of plastivores so far, and it (hopefully) won't be long until we have a solid plan on how to deal with this problem.
Dutfield, S. (2022, March 23). Plastic-eating bacteria: Genetic Engineering and Environmental impact. LiveScience. Retrieved October 20, 2022, from https://www.livescience.com/plastic-eating-bacteria
New enzyme cocktail digests plastic waste six times faster. New enzyme 'cocktail' digests plastic waste six times faster | News | University of Portsmouth. (n.d.). Retrieved October 20, 2022, from https://www.port.ac.uk/news-events-and-blogs/news/new-enzyme-cocktail-digests-plastic-waste-six-times-faster
Sadler, J. C., & Wallace, S. (2021, June 10). Microbial synthesis of vanillin from waste poly(ethylene terephthalate). Green Chemistry. Retrieved October 20, 2022, from https://pubs.rsc.org/en/content/articlelanding/2021/gc/d1gc00931a#!divAbstract
Sanluis-Verdes, A., Colomer-Vidal, P., Rodriguez-Ventura, F., Bello-Villarino, M., Spinola-Amilibia, M., Ruiz-Lopez, E., Illanes-Vicioso, R., Castroviejo, P., Aiese Cigliano, R., Montoya, M., Falabella, P., Pesquera, C., Gonzalez-Legarreta, L., Arias-Palomo, E., Solà, M., Torroba, T., Arias, C. F., & Bertocchini, F. (2022, October 4). Wax worm saliva and the enzymes therein are the key to polyethylene degradation by Galleria Mellonella. Nature News. Retrieved October 20, 2022, from https://www.nature.com/articles/s41467-022-33127-w
Sun, J., Prabhu, A., Aroney, S. T. N., & Rinke, C. (2022, June 9). Insights into plastic biodegradation: Community composition and functional capabilities of the superworm (Zophobas Morio) microbiome in styrofoam feeding trials. Microbial Genomics. Retrieved October 26, 2022, from https://www.microbiologyresearch.org/content/journal/mgen/10.1099/mgen.0.000842
Vanillin market. Future Market Insights. (n.d.). Retrieved October 21, 2022, from https://www.futuremarketinsights.com/reports/vanillin-market
Zrimec, J., Kokina, M., Jonasson, S., Zorrilla, F., & Zelezniak, A. (n.d.). Plastic-degrading potential across the global microbiome correlates with recent pollution trends. mBio. Retrieved October 26, 2022, from https://pubmed.ncbi.nlm.nih.gov/34700384/