Engineered plastic-eating enzymes as high-performance catalyst in plastic-recycling industry
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The plastic problem is vast, complex, and global. Due to the accumulation of post-consumer synthetic plastic waste, which are highly resistant to many physical, chemical, and biological factors, plastic pollution has become a global concern in any sector of the human society.
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Recycling is considered the best ways for waste management and valorization of plastic materials. Particularly, in a circular economy perspective, find a way to break down plastic in a sustainable, environmental-friendly, and cost-effective process is a key factor to the fight against the pollution.
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In this context, biotechnological approaches (e.g., the ones based on the exploitation of proteins and microorganisms) offer a feasible solution for the challenges generated by the accumulation of plastic waste.
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Plastics with hydrolysable esters, such as PET, represent an ideal target for their enzyme-mediated transformation into well-defined monomers (or oligomers). The molecules produced by this depolymerization can be used either as building blocks to synthesize new plastic products (recycling process) or as feedstocks that are converted into high added-value molecules (upcycling process).
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Concerning the biological degradation of plastic contaminants, a key role is played by the PET-hydrolysing enzymes (PHEs). Although the PHEs are of potential biotechnological interest, their application as biocatalysts in large-scale processes is currently not feasible, due to their modest catalytic performance and inadequate stability under industrial conditions.
In this context, the proposed project aims at the production of an efficient polyester hydrolase suitable for PET degradation, through the application of protein engineering strategies.
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In the Protein Factory 2.0 laboratories, we produced a newly engineered biocatalyst capable of breaking down more than 95% of post-consumer PET waste in only 3 days of incubation at 55 °C, without adding chemicals or using high temperatures, representing a more efficient solution in terms of energy demand for the whole process.
