Impacts of Biofilm Formation on the Physicochemical Properties and Toxicity of Microplastics: A Concise Review

Microplastics (MPs) are of global concern due to their slow degradation in the environment and the potential of inducing adverse effects on organisms. In aquatic ecosystems, microbes routinely colonize MPs and develop biofilms on their surfaces. Biofilms are assemblages of surface-associated microbial cells that are enclosed in an extracellular polymeric substance. Emerging evidence has suggested that the development of biofilm can alter the physicochemical properties and the pollutant adsorption capability on MPs. In this article, we review the impacts of biofilm formation on MP properties, ecotoxicity, and fate. First, we summarize the environmental factors that modulate biofilm formation, as well as the unique components of biofilm on MP. Next, we review current understanding on the influence of biofilm formation on the physical and chemical properties of MPs and discuss how these changes affect their pollutant adsorption capacity. Finally, we discuss how biofilm formation on MPs affects their ingestion by organisms and nutrient cycling in aquatic environments. [GRAPHICS]