PETases

Polyethylene terephthalate is one of the most used types of plastics. Specifically, it's used for packaging purposes. Its properties, coupled with its immense use throughout the world, have been collected throughout habitats and ecosystems, leading to it posing a significant danger to the world and global health. Currently, around 29.1% of PET bottles and jars are recycled, a statistic that is extremely low. Additionally, current thermomechanical and chemical solutions do not seem as effective and possible as a strong solution that can properly biodegrade PET.  Enter in PETases. 

PETases are a category of enzymes and are found in bacteria such as Ideonalla sakaiensis, and have exhibited PET degrading capabilities under certain conditions. PETases essentially catalyzes the hydrolysis of PET and splits it into MHET, TPA, and BHET. The bacteria then can use these products to help with growth. It can also be used to make new plastics which can help put a stop to plastic pollution. Currently, the PETase from the Ideonalla sakaiensis has shown to be the most effective when it comes to degrading PET. 

Currently, there are still huge drawbacks and roadblocks when it comes to having PETases be used  commercially to help recycle PET. PETase has been found to only work efficiently in very specific conditions, leading to issues in making it work on a larger scale. To help solve this issue, there have been multiple attempts and progress in creating engineered PETase to degrade PET more efficiently. One example of this would be HotPETase, which can function at higher temperatures than its regular counterpart. Even then, many of the current PETase are unable to degrade PET at a level that can be used at a more massive range.  

PETase has shown really strong potential in being a possible biodegradation solution to the imminent threat that PET poses to the environment and health of the people. Current advancements through protein engineering have made PETase a more effective solution, but further progress is still needed as there are slow degradation rates and issues with temperature and certain conditions. Even though it is highly promising, it is not currently at the level to be an industry-wide solution. 

References:

Wang, Tao, et al. “Molecular Engineering of PETase for Efficient PET Biodegradation.” Ecotoxicology and Environmental Safety, vol. 280, 3 June 2024, p. 116540, www.sciencedirect.com/science/article/pii/S014765132400616X, https://doi.org/10.1016/j.ecoenv.2024.116540.

Arnal, Grégory, et al. “Assessment of Four Engineered PET Degrading Enzymes Considering Large-Scale Industrial Applications.” ACS Catalysis, vol. 13, no. 20, 26 Sept. 2023, pp. 13156–13166, pubs.acs.org/doi/10.1021/acscatal.3c02922, https://doi.org/10.1021/acscatal.3c02922.

Karunatillaka, Isuru, et al. “Novel Putative Polyethylene Terephthalate ( PET ) Plastic Degrading Enzymes from the Environmental Metagenome.” Proteins: Structure, Function, and Bioinformatics, 22 Sept. 2021, https://doi.org/10.1002/prot.26245.

Alam, Intikhab, et al. “Widespread Distribution of Bacteria Containing PETases with a Functional Motif across Global Oceans.” The ISME Journal, 10 June 2025, academic.oup.com/ismej/article/19/1/wraf121/8159680, https://doi.org/10.1093/ismejo/wraf121.

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