Microbial colonization of microplastic (MP) in aquatic environments: MP toxicity, microbial degradation potential and their interactions

Microbial plastic biodegradation is one sustainable approach in reducing the accumulated plastic wastes in the environments, but specific interactions between microplastic (MP) and microorganism are still lacking. This study systematically reviews the influences of MP on cell functions and community structures of microorganisms, as well as the microbial impacts on the fate of MP within aquatic environments. Detailed examinations of their distinctive interactions within various aquatic ecosystems are also presented. While MP are commonly toxic to most microorganisms, they could also enrich specific microbial groups such as pathogens and hydrocarbon-degrading bacteria due to the chemotaxis and easier nutrition access of microorganisms. On the other hand, microorganisms are capable of secreting extracellular enzymes that biodegrade MPs into oligomers, dimers, and monomers, hereby changing the density, crystallinity, and surface roughness of MPs, consequently influencing the MP distribution patterns in aquatic environments. Additionally, we discuss current study limitations and future prospects, providing a comprehensive foundational overview for further investigations.