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Published on: October 29, 2013
Supercharged binding modules can modulate engineered poly(ethylene terephthalate) hydrolase thermostability and
Biorxiv : the Preprint Server for Biology
|June 5, 2026
Summary
Engineering enzymes for plastic degradation shows promise. A modified PET hydrolase with enhanced thermostability improved Poly(ethylene terephthalate) (PET) breakdown, especially on intact plastic surfaces, offering a new bioremediation strategy.
Area of Science:
- Biotechnology
- Environmental Science
- Polymer Science
Background:
- Poly(ethylene terephthalate) (PET) is a persistent plastic pollutant due to its recalcitrant nature.
- Enzymatic depolymerization offers a sustainable route for PET recycling and bioremediation.
- Challenges include PET's insolubility, crystallinity, and the limited thermostability of PET hydrolases.
Purpose of the Study:
- To investigate the impact of engineered surface charge on PET hydrolase activity and thermostability.
- To enhance the degradation efficiency of PET hydrolases for bioremediation applications.
- To explore the relationship between PET binding affinity and catalytic performance.
Main Methods:
- Fusion of electrostatically supercharged PET binding modules (PBMs) to a Cutinase Catalytic Domain (CD) from *Thermobifida fusca*.
- Characterization of PET binding interactions using pull-down assays.
- Assessment of hydrolysis activity on milled PET powder and intact PET discs.
- Thermostability analysis using melting temperature determination.
Main Results:
- Positively supercharged PBMs showed stronger binding to negatively charged PET but did not improve hydrolysis.
- A slightly negatively charged PBM-CD fusion (D2 construct) exhibited comparable activity on milled PET and superior activity on intact PET discs.
- The D2 construct showed a 10 °C increase in melting temperature, leading to enhanced catalytic persistence.
- Long-term hydrolysis activity increased 2-fold on milled PET and up to 10-fold on intact PET discs for the D2 construct.
Conclusions:
- Enzyme thermostability is a critical factor for functional persistence in PET hydrolysis, more so than binding affinity alone.
- Engineered PET hydrolases with improved thermostability show significant potential for depolymerizing minimally processed PET feedstocks.
- This study provides insights into designing robust enzymes for effective plastic bioremediation.
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