Cleaning Up the Smallest Pollutants: The Potential of Microbial Degradation in Tackling Micro- and Nano-Plastic Pollution

Microplastics (MPs) and nanoplastics (NPs) have become increasingly alarming subjects due to their widespread presence and their potential harm to the environment. The micro-nano plastics (MNPs) are emerging as an environmental hazard as they enter the agroecosystem, plants, animals, and human body via trophic levels, through ingestion or inhalation, causing a variety of issues such as disruption in the blood-brain barrier, abnormalities, and reduced fertility. Therefore, it is essential to create innovative MNP remediation techniques for their removal from the natural environment. Microbial remediation, one of the available techniques, has the potential to be a successful green technique for destroying/recovering MNPs. The breakdown of MNPs by microorganisms like bacteria, fungi, and microalgae in both axenic and mixed cultures can be viewed as an environmentally sustainable method for addressing the issue of microplastic pollution. As microbial remediation techniques rely on various biotic and abiotic factors, including temperature, pH, and oxidative stress, it is now possible to manipulate these factors to bring about changes in plastic pollutants. Therefore, it is important to identify the primary pathways that microbes use to break down plastic components as the only carbon source used by microorganisms for their growth and development. In this chapter, the role of different microorganisms and their enzymatic processes in degrading MNPs in diverse environmental compartments, such as wastewater (WW) streams, municipal sludge, municipal solid waste (MSW), and composting, is described. The chapter also discusses the advantages and disadvantages of several MNP remediation technologies, including enzymatic, advanced molecular, and biomembrane systems, as well as their potential for further study.