On average, 380 million tons of plastic waste is produced every year, and more than 10 million tons of the plastic is dumped into the ocean annually. This is a cause for concern, as these plastics eventually break down into tiny particles, called microplastics, which attract toxins that can cause diseases in wildlife and ultimately, as the concentration of micro plastics increases the further up the food chain that it travels, humans (Plastic Pollution Facts, 2021). However, in 2016, a solution began to arise in the form of a new bacterium, Ideonella sakaiensis, which was found in a mud puddle behind a plastic bottle recycling plant in Osaka, Japan.
Thanks to its digestive enzymes, Ideonella sakaiensis is able to break down polyethylene terephthalate (PET) plastic, due to their environment being degraded by our waste to the point that it caused a mutation. The mutation is rapid, however, even with 400 identified species of these plastic-eating fungi and bacteria, their species there would need to be genetic modification to increase the rate at which these bacteria and fungi are able to breakdown and digest plastics by hundreds or thousands of times faster for them to be useful to the depletion of plastic waste (The SeaCleaners | Mutant Plastic-Eating Bacteria: Sci-Fi or Plan B against Plastic Pollution?, “Fast and Furious: 400 species of fungi and bacteria have evolved”, section, 2023, June 17).
In industrial research, enzymatic recycling is the topic that has been taken up, in which “super-enzymes” are being developed. These new enzymes along with genetically modified organisms, designed to break down polymer chains, are being developed to degrade plastic waste at faster rates. Carbios, a French technology company, had a breakthrough with enzymatic recycling, creating new products using these degraded plastics and textile waste, revolutionizing the circular economy, a concept in which raw materials is kept within a closed loop. Since 2021, Caribos has been using the plastic- eating enzyme, PET hydrolase, at a demonstration plant in Central France, which was modified to work faster and at higher temperatures(Carbios, n.d.).
This is not a one for all solution however, as current thermomechanical recycling processes are limited to only temporarily maintaining clear plastics in the circular economy, due to the quality deteriorating over time, thus, making it very difficult or impossible to recycle complex and soiled plastics. The monomers from the depolymerixation are only able to repolymerized into a quality that is equivalent to the original PET that was purified, similar not the same.
While the use of plastic-eating bacteria and fungus to reverse the effects of PET plastics is not able to be used for large masses of plastic waste in dumps and oceans, the use of these enzymes was an important landmark in the way how raw materials used to make plastics are now able to be recycled and repurposed.
By Lauren Lewis
References
Plastic Oceans International. (2018). Plastic Pollution Facts. Plastic Oceans International.
Ocean Plastic Facts - Just One Ocean. (n.d.).
The SeaCleaners | Mutant plastic-easting bacteria: sci-fi or plan B against plastic pollution? (2023, June 17). The SeaCleaners.
New LIFE for waste plastic - European Commission. (n.d.). Cinea.ec.europa.eu. Retrieved February 6, 2024, from
Carbios. (n.d.). Enzymatic recycling. Carbios.
Earthdat.org. (2022, March 29). Fact Sheet: Single use Plastics | Earth Day. Earth Day.
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