Adaptive laboratory evolution enables microbial access to untreated, virgin high-density polyethylene under...

Area of Science:

• Environmental microbiology
• Polymer science
• Biotechnology

Background:

• Synthetic plastics, especially high-density polyethylene (HDPE), are persistent environmental pollutants due to their resistance to degradation.
• The crystalline and hydrophobic nature of HDPE hinders microbial colonization and breakdown, making its biodegradation challenging.
• Existing studies often rely on pretreated HDPE, leaving the microbial degradation of untreated, virgin HDPE largely uninvestigated.

Purpose of the Study:

• To isolate microorganisms capable of degrading untreated, virgin high-density polyethylene (HDPE).
• To explore the potential of adaptive laboratory evolution (ALE) for enhancing microbial degradation of recalcitrant plastics.
• To demonstrate the biological mineralization of HDPE under environmentally relevant conditions.

Main Methods:

• Utilized adaptive laboratory evolution (ALE) with activated sludge and landfill samples as inocula.
• Cultivated microbial communities in a mineral salt medium with virgin HDPE as the sole carbon source.
• Isolated and identified microbial strains showing HDPE degradation capabilities.

Main Results:

• Successfully isolated Pandoraea sp. B8 through long-term ALE.
• Demonstrated reproducible surface deterioration of HDPE films by Pandoraea sp. B8.
• Confirmed biological mineralization of HDPE via measurable carbon dioxide evolution, indicating genuine degradation.

Conclusions:

• Adaptive laboratory evolution (ALE) can effectively select for microorganisms capable of degrading untreated HDPE.
• Microbial degradation of virgin HDPE is achievable under environmentally plausible conditions without physicochemical pretreatment.
• This study offers a promising strategy for addressing plastic pollution by harnessing microbial adaptation.