Parts | Days | Selection | Search | Updates | Downloads | Help

SYSC: Symposium The Sustainability Challenge: A Decade of Transformation

SYSC 1: The Sustainability Challenge: A Decade of Transformation

SYSC 1.3: Invited Talk

Monday, March 9, 2026, 16:00–16:30, HSZ/AUDI

Mechanistic and Material Perspectives on Enzymatic Hydrolysis of Semicrystalline Polyesters — •Birte Höcker — Biochemie, Universität Bayreuth, Germany

Enzymatic degradation of polyethylene terephthalate (PET) provides a sustainable route for polyester recycling, yet efficiency remains limited by both enzyme diversity and substrate properties. To address this, we developed a tunable degradation platform incorporating realistic substrates and adaptable to various polyesters, enabling parallelized purification and high-throughput characterization of novel enzymes and engineered variants. Using this system, we identified halophilic PETases from the marine Halopseudomonas lineage. High-resolution crystallography of one candidate revealed a unique active-site architecture lacking the canonical π-stacking clamp and exhibiting altered loop conformations, prompting an extension of the PETase classification to include type III enzymes. These enzymes demonstrated remarkable salt tolerance and improved PET hydrolysis at elevated temperatures. Complementary studies on polybutylene terephthalate (PBT) highlight the critical role of semicrystalline morphology: reducing crystallinity and optimizing incubation near the glass transition significantly enhance hydrolysis. By expanding the structural and sequence space of PET-degrading enzymes, combined with material-specific insights, we aim to establish a foundation for efficient enzymatic recycling of semicrystalline polyesters and support the development of next-generation biocatalysts for sustainable plastic management.

Keywords: PETase; plastic degradation; polyester hydrolysis; enzyme; microplastic