Does bacterial community succession within the polyethylene mulching film plastisphere drive biodegradation?

Area of Science:

• Environmental Microbiology
• Polymer Science
• Agricultural Science

Background:

• Agricultural fields face significant contamination from polyethylene mulching film (PMF).
• Microorganisms colonizing PMF in the environment form distinct biofilms, known as the plastisphere.
• Understanding these microbial communities and their interaction with PMF is crucial for addressing plastic pollution.

Purpose of the Study:

• To investigate the succession of soil microbial communities within the PMF plastisphere.
• To explore the potential for PMF degradation by these specialized plastisphere communities.
• To analyze changes in microbial diversity and function related to plastic degradation.

Main Methods:

• Utilized an artificial micro-ecosystem to simulate agricultural conditions.
• Employed scanning electron microscopy (SEM) and confocal laser scanning microscopy for biofilm visualization.
• Applied atomic force microscopy, Fourier transform infrared spectroscopy, and water contact angle measurements to analyze film surface changes.
• Conducted Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) for functional gene prediction.

Main Results:

• Observed a significant decrease in bacterial alpha diversity in the plastisphere and surrounding liquid.
• Identified enrichment of microbial phyla and genera capable of degrading polyethylene and hydrocarbons within the plastisphere.
• Detected increased metabolism pathways for Xenobiotics Biodegradation and Metabolism, suggesting polyethylene degradation potential.
• Confirmed biofilm formation and significant alterations in PMF surface microstructure, chemical composition, and hydrophobicity.

Conclusions:

• The PMF plastisphere harbors distinct microbial communities with the capacity to degrade polyethylene.
• Microbial succession in the plastisphere leads to changes in soil microbial community structure and function.
• This research provides critical insights into the biodegradation of agricultural plastic mulching films by soil microorganisms.