Mechanoenzymatic reactions for the hydrolysis of PET

Recent advances in the enzymatic degradation of poly(ethylene terphthalate) (PET) have led to a number of PET hydrolytic enzymes and mutants being developed. With the amount of PET building up in the natural world, there is a pressing need to develop scalable methods of breaking down the polymer into its monomers for recycling or other uses. Mechanoenzymatic reactions have gained traction recently as a green and efficient alternative to traditional biocatalytic reactions. For the first time we report increased yields of PET degradation by whole cell PETase enzymes by up to 27-fold by utilising ball milling cycles of reactive aging, when compared with typical solution-based reactions. This methodology leads to up to a 2600-fold decrease in the solvent required when compared with other leading degradation reactions in the field and a 30-fold decrease in comparison to reported industrial scale PET hydrolysis reactions.

Automated summary

Recent advances in enzymatic degradation of PET have resulted in the development of various PET hydrolytic enzymes and mutants. Scaling up methods for breaking down PET into its monomers for recycling or other purposes is urgently needed due to the accumulation of PET in the environment. Mechanoenzymatic reactions have become a promising alternative to traditional biocatalytic reactions. In this study, we report a significant increase in the yields of PET degradation by whole cell PETase enzymes by using ball milling cycles, leading to reduced solvent requirements compared to other degradation reactions and industrial scale PET hydrolysis reactions.