Harnessing microorganisms for multiscale biodegradation of microplastics and nanoplastics in terrestrial and aquatic environments

Micro- and nanoplastics (MnPs) are now widely distributed across terrestrial and aquatic ecosystems due to the continuous input of plastic waste, including packaging materials, beverage containers, and agricultural mulch films. Although MnPs have long been regarded as highly persistent and largely non-biodegradable, emerging evidence suggests that measurable biodegradation may occur under favorable environmental conditions, with reported degradation rates exceeding 10% in some cases. Such conditions include ultraviolet (UV) irradiation, elevated temperatures, adequate moisture, and the presence of specialized microbial communities. These findings challenge conventional assumptions regarding the environmental persistence of MnPs and indicate potential opportunities for microbial-based remediation strategies. However, significant knowledge gaps remain. The mechanisms governing MnP biodegradation, environmental transport, and transformation processes are still poorly understood, and uncertainties persist regarding their long-term ecological and human health impacts. In addition, effective translation of laboratory-scale observations into scalable, real-world remediation strategies remains a major challenge. This review synthesizes current knowledge of MnP–microorganism interactions, emphasizing multiscale processes and the key barriers that limit field application. We examine microbial degradation pathways and their effects on microbial community structure and function, while identifying critical gaps in mechanistic understanding. Given the strong coupling between plants and microbial communities in natural ecosystems, we further highlight plant–microorganism–MnP interactions as an underexplored but potentially important component of MnP fate and transformation. Finally, we outline research priorities for advancing MnP monitoring, risk assessment, and remediation in both terrestrial and aquatic environments. These include investigating microbial consortia and biofilm dynamics, enhancing soil-based filtration and stabilization processes, and leveraging plant–microbe interactions. We also emphasize the need to bridge laboratory, field, and landscape-scale studies to enable the development of effective, scalable MnP mitigation strategies.