Role of biofilms in the degradation of microplastics in aquatic environments

Microplastics are pollutants of emerging concern that have already gained significance in recent years because of their recalcitrant nature and their detrimental effects on living beings and the ecosystem. Due to their small size, microplastics are easily integrated into biogeochemical cycles and food webs, drastically affecting the environment. Our current knowledge on the interactions of microplastics with various components of ecosystems is limited; however, considering their potential long-term impact, massive research efforts are underway to understand the environmental fate of microplastics and any possible strategies for remediation. In marine ecosystems, plastic surfaces are mostly colonized by microorganisms that form biofilms. Plastic-biofilm interactions potentially influence the physical and chemical properties of the polymer, thereby leading to its degradation. Hence, to mitigate the foreseen nuisance of microplastics contamination, biofilms are being considered as potential candidates for the remediation of marine environments. Though the interactions between plastic and microbes are still inadequately understood, much of the research in the field is being focused on this aspect. In this review, we discuss several types and sources of microplastics, along with their trophic transfer and negative impacts on ecosystem. In addition, we focus on the current knowledge and explain the research gaps in understanding plastic-microbe interactions in marine environments, while highlighting the role of biofilms in the degradation of microplastic debris. Finally, we comment on the future aspects and research priorities in this field to further elaborate the role of microorganisms in determining the fate of microplastics in aquatic ecosystems. (c) 2021 Society of Chemical Industry (SCI).