Plastic products are a cemented part of everyday life, from containers and clothes to bags, bottles and food packaging. However, plastics resist degradation, instead breaking down into smaller particles that invade natural ecosystems and threaten the organisms living in them, including humans.
Polyethylene terephthalate (PET) – a polymer widely used in common plastic products due to its durability and cheap cost – is a primary target for scientists to reduce plastic pollution. Utilizing enzymes and other biology-based methods to break down PET in plastic show promise in the scientific community and form the basis of many novel research projects. Advanced analytical techniques, such as nuclear magnetic resonance (NMR), are essential to enabling this work and taking steps toward a sustainable economy with recycled plastic.
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Mutated LLC Provides a Promising Solution to Degrading PET in Plastic
According to a recent study from researchers based in France, tens of millions of pounds of PET are produced yearly. This PET adds to an existing amount already persisting in several ecosystems.
Scientists from Toulouse Biotechnology Institute at the Université de Toulouse and biotechnology company Carbios collaborated to address this challenge. They identified a mutated form of an enzyme called leaf-branch compost cutinase (LCC) that degraded PET.
This mutant LCC also retained the monomers of PET so that it can be repeatedly remade into high-quality plastic products, an example of how plastic can be recycled in a circular economy.
The team observed that the LCC mutant enzyme is a solution to plastic recycling and provides insight for future enzyme studies for plastic recycling.
NMR Technology Allows for Optimization of PET Degrading Enzymes
The scientists conducted NMR studies using Bruker TopSpin software to identify and analyze NMR data about the characteristics of the enzyme LCC and its mutants regarding their performance in unfolding PET. They used NMR to follow LLC through various mutations and tracked which mutation displayed improved performance in unravelling PET.
The experiments revealed the importance of binding sites, temperature and interactions with acid during the PET unfolding process.
These experiments helped the team isolate an effective PET depolymerase candidate, PETase, that had optimal binding sites and thermostability when unravelling the PET polymer. NMR revealed details about the engineered enzyme that could be crucial in further studies about the relationship between enzymes and plastic.
NMR is a unique and powerful technique for chemical analysis ranging from basic identification and quantification of substances to molecular structure elucidation and dynamics investigation. With a range of NMR systems – from cost-optimized benchtop devices to high-performance floor-standing instruments – Bruker provides a powerful solution portfolio for comprehensive value chain coverage from product innovation to manufacturing. Powered by our industry-leading analysis and acquisition software TopSpin, Bruker NMR systems enable organizations to achieve a Distributed Laboratory Topology (DLT) in which expertise, methods, and data can be easily and quickly shared between different stages in the value chain and different locations
The Future of Plastic Recycling
This paper and similar studies aim to construct methods that will reduce plastic waste and the resources needed in plastic manufacturing in efforts to move toward a circular economy. Developing solutions to recycle and reuse plastic highlights the need for innovative techniques for acquiring and analyzing complex enzyme and protein data.
The TopSpin NMR software by Bruker is used with Bruker NMR instruments to produce high-quality data from measurement through to analysis stages of research.
With efficient and accelerated analysis of NMR spectra, the research team could study a novel engineered PET-degrading enzyme, identify characteristics that signify optimal performance, and open up new directions for further investigation.
The PETase described in the publication is an ideal enzyme solution because it effectively breaks down PET and preserves its building blocks. Therefore, it can be repurposed into products with the same high-quality plastic people use today. In this cycle, a sustainable relationship with plastic is achieved.
Scientific studies such as this one pave the way for efficient plastic recycling. The circular economy can be executed and championed by innovating research and making environmentally conscious choices by consumers and policymakers.
Reference and Further Reading
Charlier, Cyril, et al. (2022) “An NMR Look at an Engineered PET Depolymerase.” Biophysical Journal, 121(15), pp. 2882–2894, https://doi.org/10.1016/j.bpj.2022.07.002 . Accessed 20 Feb. 2023.
This information has been sourced, reviewed and adapted from materials provided by Bruker BioSpin - NMR, EPR and Imaging.
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