A Cytochrome P450 Facilitates Polyethylene Metabolism in a Microbial Community

Area of Science:

• Environmental Microbiology
• Polymer Science
• Biotechnology

Background:

• Low-density polyethylene (LDPE) is a persistent environmental pollutant with limited recycling options.
• Biodegradation presents a promising alternative for managing LDPE plastic waste.
• Limited knowledge exists regarding enzymes and organisms capable of LDPE degradation.

Purpose of the Study:

• To investigate the potential of soil bacteria consortium to degrade UV-treated LDPE.
• To identify specific enzymes and metabolic pathways involved in LDPE biodegradation.
• To elucidate the role of cytochrome P450 reductase in LDPE degradation.

Main Methods:

• Cultivation of a soil bacteria consortium (Pseudomonas and Bacillus species) using UV-treated LDPE film and powder as the sole carbon source.
• Analysis of LDPE mass reduction, surface functional group changes (ATR-FTIR), and metabolic byproducts (GC/MS).
• Identification and characterization of a specific gene (CYP102 A5) encoding a cytochrome P450 reductase in Bacillus thuringiensis.

Main Results:

• The bacterial consortium reduced LDPE film and powder mass by 7% and 13% respectively over 30 days.
• ATR-FTIR confirmed chemical modifications on the LDPE surface, indicating degradation.
• GC/MS detected byproducts consistent with alkane and carboxylic acid metabolism.
• Expression of CYP102 A5 increased when bacteria were grown on LDPE; purified protein induced PE oxidation.

Conclusions:

• A consortium of soil bacteria, including Pseudomonas and Bacillus species, can effectively degrade UV-treated LDPE.
• The identified cytochrome P450 reductase (CYP102 A5) plays a significant role in the oxidation and biodegradation of LDPE.
• This research provides a key enzymatic insight into microbial degradation of polyethylene plastics.