Molecular engineering of PETase for efficient PET biodegradation.

Area of Science:

• Biotechnology
• Environmental Science
• Biochemistry

Background:

• Polyethylene terephthalate (PET) pollution necessitates sustainable degradation solutions.
• Current PET recycling methods face limitations.
• Enzyme-catalyzed biodegradation offers a promising alternative.

Purpose of the Study:

• To engineer enhanced PET-degrading enzymes and whole-cell biocatalysts.
• To improve the thermal stability and activity of PETase.
• To develop a regenerable and reusable biocatalyst for PET biodegradation.

Main Methods:

• Engineering of HotPETase (HP) and fusion with Bacillus anthracis carbohydrate-binding module (BaCBM) to create HLCB.
• Development of whole-cell biocatalyst (D-HLCB) using E. coli surface display of HLCB via FadL.
• Evaluation of enzyme activity against ester compounds and PET degradation efficiency.
• Assessment of D-HLCB reusability and stability.
• Molecular docking simulations to elucidate binding and reaction mechanisms.

Main Results:

• HP showed improved catalytic activity and longevity compared to wild-type PETase.
• HLCB exhibited enhanced PET degradation, yielding 25.5% more monomers than HP.
• The D-HLCB system achieved a high monomer yield (1.03 mM) and retained over 54.6% activity after nine cycles.
• Molecular docking provided insights into the enhanced degradation mechanisms.

Conclusions:

• Engineered HLCB and D-HLCB biocatalysts significantly improve PET biodegradation.
• The developed whole-cell system is stable, reusable, and effective under mild conditions.
• This strategy holds potential for complete and sustainable PET biodegradation.