In silico Evaluation of Cross-linkers for Immobilizing Laccase in Scalable Polyethylene Terephthalate (PET) Biodegradation
DOI:
https://doi.org/10.11113/bioprocessing.v5n1.93Keywords:
Enzyme immobilization, molecular docking, Molecular dynamics, PET biodegradationAbstract
The rapid accumulation of polyethylene terephthalate (PET) in the environment has intensified the need for sustainable and efficient strategies for plastic degradation. Laccase, a flexible oxidoreductase able to attack and cleave the ester linkage for potential PET hydrolysis, is hindered in practical applications by limited stability, restricted reusability, and susceptibility to industrial conditions. This study employed in silico approaches, including molecular docking and molecular dynamics (MD) simulations, to evaluate the interactions and stability of laccase immobilized with a diverse set of cross-linkers: micromolecular (ethylene glycol, glutaraldehyde, and benzoquinone), macromolecular (chitosan, and dextran), and polysaccharide-based (amylopectin, dextran, and glucosamine). Among these, glucosamine exhibited the strong binding affinity, with ΔG values of –7.0 kcal/mol (AutoDock) and –7.98 kcal/mol (SwissDock), forming 4–7 persistent hydrogen bonds at a safe distance of 15–21 Å from the T1 copper catalytic centre. MD simulations over 10 ns confirmed enhanced structural stability of the laccase + glucosamine complex, evidenced by low RMSD values (~0.20–0.28 nm), reduced RMSF at catalytic loops (0.02–0.07 nm), consistent Rg (1.68–1.74 nm), and decreased SASA (175–185 nm²). According to these findings, glucosamine offers excellent structural stability, compactness, and preservation of active site integrity, highlighting its potential use as a biocompatible cross-linker. The study establishes an appropriate in silico framework for developing reliable immobilized laccase systems for industrial and environmental PET degradation applications.
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