Author(s) :

Audrey Xie.

Volume/Issue :

Abstract :

Microplastics (MPs) are pervasive in aquatic environments and pose significant ecological and health concerns. Considerable attention has been given to the process and methods for reducing and degrading MPs. Many studies focus on the processes separately, and few mention the combined effect of MP degradation. This review evaluates two key methods of MP reduction, photodegradation under sunlight and microbially mediated biodegradation, and highlights the role of periphytic biofilms in modulating these processes. Photoaging, driven by UV radiation and reactive oxygen species (ROS), changes MP surface chemistry, morphology, and fragmentation behavior in ways that depend on polymer type, pigment, and environmental condition. Conversely, biodegradation involves microbial and biofilm-mediated conversion of MPs into simpler compounds, with rates that are influenced by polymer chemistry, community composition, and environmental factors. Recent studies reveal that biofilms can inhibit MP photoaging by shielding particle surfaces from UV light, while also altering microbial community composition, MP surface properties, and degradation kinetics. Despite advances in understanding mechanisms of biofilm colonization, photoaging, and biodegradation independently, their coupled effects remain poorly characterized. A deeper understanding of biofilm–MP–light interactions is essential for developing conceptual models and sustainable remediation strategies to mitigate plastic pollution in aquatic ecosystems.