New insights on municipal solid waste (MSW) landfill plastisphere structure and function

Area of Science:

• Environmental Microbiology
• Microbial Ecology
• Biogeochemical Cycles

Background:

• Plastisphere, the microbial community on plastic surfaces, plays a key role in global carbon and nitrogen cycles.
• Municipal Solid Waste (MSW) landfills are significant anthropogenic sources of methane and nitrous oxide, with plastics constituting 42% of waste.
• Limited knowledge exists regarding the microbial communities and biogeochemical functions within landfill plastispheres.

Purpose of the Study:

• To characterize and compare the organic chemical profiles, bacterial community structure, and metabolic pathways of landfill plastisphere and surrounding refuse.
• To investigate the role of landfill plastispheres in microbial carbon and nitrogen cycling.
• To identify factors influencing bacterial community composition on plastic surfaces in landfills.

Main Methods:

• Gas Chromatography-Mass Spectrometry (GC/MS) for organic chemical profiling.
• 16S rRNA gene high-throughput sequencing for bacterial community structure analysis.
• Bioinformatic analysis to predict metabolic pathways and functional genes.

Main Results:

• Landfill plastisphere and surrounding refuse exhibited distinct organic chemical compositions, with evidence of plastic additive leaching.
• Bacterial richness was significantly higher on plastic surfaces than in surrounding refuse.
• Distinct bacterial communities were observed, with genera like Pseudomonas dominating plastic surfaces and Bacillus dominating surrounding refuse.
• Plastisphere showed significantly higher abundance of functional genes involved in carbon metabolism and nitrification.
• pH was identified as a primary driver of bacterial community structure on plastic surfaces.

Conclusions:

• Landfill plastispheres represent unique ecological niches harboring distinct microbial communities.
• These microbial communities exhibit enhanced activity in carbon and nitrogen cycling processes.
• The findings underscore the importance of landfill plastispheres in landfill ecosystems and their potential impact on global biogeochemical cycles.