Enzymatic depolymerization of polyethylene using a small laccase and its potential for bio-upcycling

Area of Science:

• Biotechnology
• Environmental Science
• Polymer Science

Background:

• Polyethylene (PE) plastics pose significant environmental challenges due to their persistence.
• Biological solutions for PE degradation are urgently needed.

Purpose of the Study:

• To investigate the potential of a novel small laccase, ASLAC from Amycolatopsis sp. ATCC 39116, for polyethylene biodegradation.
• To evaluate ASLAC's efficacy in degrading PE and its utilization by Yarrowia lipolytica.

Main Methods:

• Expression of ASLAC in Yarrowia lipolytica and assessment of biomass production using PE as a carbon source.
• Surface analysis of PE films using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) after ASLAC treatment.
• Structural analysis, molecular docking, and phylogenetic analysis of small laccases.

Main Results:

• ASLAC demonstrated the highest biomass production among tested laccases when expressed in Y. lipolytica.
• SEM and AFM confirmed substantial degradation of PE films treated with purified ASLAC.
• Degradation products of PE were utilized by Y. lipolytica, indicating potential for bioenergy conversion.
• ASLAC's optimized hydrophobic binding site and Type-Ia classification correlate with superior PE degradation capabilities.

Conclusions:

• ASLAC is a potent biocatalyst for the sustainable degradation of polyethylene.
• This research provides a foundation for bioremediation and upcycling of PE plastics using ASLAC.