Summary Reader Response (Draft 1)

The article, “Plastic-eating Enzyme Could Eliminate Billions of Tons of Landfill Waste'' by The University of Texas at Austin (2022), revealed that researchers at The University of Texas at Austin have developed an enzyme variant that can accelerate the degradation of environmentally harmful plastics in hours or days instead of centuries. The researchers mainly focused on polyethylene terephthalate (PET), a polymer most commonly found in consumer packaging and certain fibers and textiles. This enzyme variant is able to disintegrate the plastic into smaller parts (depolymerization) and then put it back together (repolymerization) which begins the upcycling process. Plastic eating enzymes were first created in 2016. Among the factors that have hindered the application of this plastic-eating enzyme are its inability to function at low temperatures and different pH ranges, its inability to treat untreated plastic waste directly, and its slow reaction times (Malewar, 2022). 

However, this new and improved enzyme variant is proven to be superior in breaking down PET plastics more efficiently. This enzyme has the potential to remove waste from landfills and green high-waste industries, which would be a significant contribution to the cleanup of landfills and greening of high-waste industries. The recycling of plastic could lead to a more sustainable approach as well compared to traditional recycling methods. Even so, reducing plastic pollution in the first place is crucial. The enzyme is certainly not the solution, but rather an essential component. Today's environmentally conscious generation wonders what would happen to plastic once it reaches its end of life, or becomes worn out. The whereabouts of single-use plastic in the case that it cannot be recycled. Unfortunately, the waste is disposed of in landfills. According to the European Union (EU), up to 80% of ocean waste consists of plastic. As plastic can survive in landfills for hundreds of years due to its resistance to degradation, these versatile materials become environmental nightmares. Modifiers, such as pigments or fillers, may also be present in the plastic, which can cause problems during the decomposition process (BioLabTests, 2022).

Current plastic recycling methods can be generally classified into mechanical and chemical approaches. For years, mechanical recycling has been used to recycle plastic waste at large scale. The process involves sorting, washing, grinding, and extruding plastics into raw materials for reuse. Mechanical recycling, on the other hand, is normally a downcycling process since the quality of the reprocessed plastic material will significantly degrade and the end product will be of lower value (Mechanical Recycling | Circular Economy Asia, n.d.). 

Recycling of plastic waste involves chemical reactions that recover small molecules from the waste. Due to its inability to perform under harsh conditions, this method is not widely used in reaction conditions and requires large energy input and costly chemical catalysts. Despite the fact that incineration recovers heat energy, it produces greenhouse gasses and toxic airborne compounds, making it less environmentally friendly than other recycling methods.

However, in contrast, enzymatic conversion of plastic waste could operate under reaction conditions. It demonstrates superior degradation of PET plastic at a low temperature of 30 to 50 °C (86 to 122 °F), a variety of pH levels and pressure. In some experiments, it broke down plastics in as little as 24 hours after degrading 51 different untreated PET products within a week. As part of the process, the scientists used FAST-PETase to break down the plastics, and then reconstructed them chemically using the recovered monomers (Lavars, 2022). Compared to chemical recycling processes, enzymes are more time-saving and consume less energy, therefore reducing energy and reagent consumption. Additionally, it offers new opportunities for ‘upcycling’. Plastic substrates can be depolymerized by enzyme biocatalysis into oligomers and monomers, which can then be reprocessed into new plastic products or refined into new value-added chemicals in a circular economy. In this case, plastics would be reused indefinitely and eliminate reliance on fossil fuels resources. According to research (Cobongela, 2021), polyester, polyamides (PA), and polyurethanes (PU) are among the plastics that are hydrolyzable by most enzymes reported so far. There are only a limited number of reports on enzymes that degrade non-hydrolyzable plastics since they are extremely resistant to biological cleavage.

As a product packaging may contain a bad mixture of plastic in which has three, four, up to 12 layers of different plastics. Also not to mention, enzymes only can work in the environment at ambient temperature. Despite enzymatic plastic degradation being a more environmentally friendly method of recycling plastic waste, it has remained a topic to be explored further with major improvement.  

Enzymatic plastic recycling, with improved techniques, reduced plastic production, and public incentives, has the potential to be an excellent tool to combat the problem of plastic pollution in the near future. However, according to ISM Waste & Recycling (2021), the most vital solution is prevention which means reducing the amount of plastic used in the first place. There will be less need for product reuse, less trash to be disposed of, and most significantly, less trash to be dumped in landfills. Also, by using fewer and eliminating unneeded materials while designing, producing, and packing items, we can reduce plastic waste. Additionally, employing less dangerous waste products whenever possible.

References

BioLabTests. (2022, July 22). Plastic-eating bacteria: a solution to plastic pollution? BioLabTests. https://biolabtests.com/plastic-eating-bacteria/

Can plastic-eating enzymes solve the recycling problem? (n.d.). Home - FT Channels. Retrieved February 7, 2023, from https://channels.ft.com/en/rethink/can-plastic-eating-enzymes-solve-the-recycling-problem/

Cobongela, S. Z. Z. (2021). Enzymes Involved in Plastic Degradation. Degradation of Plastics, 95–110. https://doi.org/10.21741/9781644901335-4

ISM Waste & Recycling. (2021, June 24). What is the Waste Hierarchy? ISM Waste & Recycling. https://ismwaste.co.uk/help/what-is-the-waste-hierarchy

Lavars, N. (2022, April 28). Fast-acting enzyme breaks down plastics in as little as 24 hours. New Atlas. https://newatlas.com/environment/fast-acting-enzyme-plastics-24-hours/

Levy, N. (2022, April 27). Plastic-eating Enzyme Could Eliminate Billions of Tons of Landfill Waste. UT News. https://news.utexas.edu/2022/04/27/plastic-eating-enzyme-could-eliminate-billions-of-tons-of-landfill-waste/

Malewar, A. (2022, April 28). Plastic-eating enzymes can break down plastics in as little as 24 hours. Inceptive Mind. https://www.inceptivemind.com/plastic-eating-enzymes-break-down-plastics-24-hours/24446/

Mechanical Recycling | Circular Economy Asia. (n.d.). Circular Economy Asia. https://www.circulareconomyasia.org/mechanical-recycling/