Plastisphere Assembly and Surface Transformation of Common Plastics across Environments

Plastic waste in the environment has a significant adverse effect on ecosystems and human health. Plastic biodegradation has been observed in certain environments as a potential strategy for end-of-life plastics management. Recent research has focused on plastispheres, a microbial biofilm that forms on plastic surfaces. The plastisphere might play an important role in microbial colonization, polymer surface modification, and potential biodegradation processes. Nevertheless, there have been limited studies on plastispheres across different polymer types and environments, especially in different environmental compartments. Microbial communities associated with five types of plasma-treated plastics, high-density polyethylene (HDPE), low-density polyethylene (LDPE), poly(ethylene terephthalate) (PET), polypropylene (PP), and polyurethane (PUR), were observed across three different environments (i.e., activated sludge, landfill soil, and estuarine sediments). Results revealed distinct surface transformation patterns and plastisphere community shifts for each plastic type, which varied across environmental matrices and polymer types. Community-level analyses showed that the environmental matrix was the dominant driver of genus-level plastisphere structure. Within individual matrices, polymer identity was associated with community differentiation and genus-level enrichment patterns. In landfill soils, Rhodococcus and Sulfobacillus were enriched in the HDPE- and PET-associated plastispheres, respectively, indicating polymer-associated enrichment of candidate plastisphere-associated taxa. In estuarine sediments, SEM and FTIR analyses showed evidence of morphological and chemical transformations occurring at the surface of all plasma-treated plastics. Pseudomonas was enriched within several plastispheres and was one of the most dominant genera associated with estuarine plastisphere communities. This study provides information about the plastisphere of different plastics in different environments and helps us better understand how environmental matrix primarily shapes plastisphere assembly, with additional polymer-associated variation within individual environments. This could also help guide future studies and monitoring strategies for plastic-associated biofilms in diverse environments.