A comprehensive mechanism of polyester enzymatic depolymerization: A novel singular key parameter for streamlined...

Area of Science:

• Polymer Science
• Biotechnology
• Environmental Science

Background:

• Plastic pollution is a persistent global challenge due to the inherent stability of polymers.
• Current research often segregates enzymatic and non-enzymatic plastic degradation, overlooking their practical interplay.
• Developing sustainable solutions like eco-design and enzymatic recycling is crucial for mitigating plastic waste.

Purpose of the Study:

• To unify the understanding of plastic depolymerization into a single, simplified mechanism.
• To identify key factors governing both enzymatic and non-enzymatic degradation pathways.
• To establish a novel parameter for optimizing enzymatic plastic recycling.

Main Methods:

• Utilized polylactide (PLA) as a model polymer for studying depolymerization.
• Introduced and measured the local glass transition temperature of the soaked material (T_g^s).
• Investigated the interplay between chain mobility, enzymatic hydrolysis, and non-enzymatic depolymerization.

Main Results:

• Identified T_g^s as the central factor enabling polymer chain mobility essential for enzyme interaction.
• Demonstrated that chain mobility is the primary driver of plastic degradation.
• Showed that enzymatic hydrolysis initiates degradation, which can then trigger non-enzymatic depolymerization.

Conclusions:

• Proposed a unified mechanism for plastic depolymerization, integrating enzymatic and non-enzymatic processes.
• Highlighted the significance of T_g^s in facilitating efficient enzymatic recycling.
• Provided a novel pathway to accelerate polyester degradation under realistic environmental conditions.