A systematic review of the mechanisms underlying the interactions between microplastics and microorganism in the environment

Microplastics (MPs) may be accidently ingested by many organisms due to their small size (<5 mm), and their accumulation along the food chain poses a serious threat to ecosystem health. Microorganism can directly or indirectly affect the morphology, properties, eco-toxicity, and degradation of MPs in the environment. The present review mainly aims to reveal the interaction mechanism of MPs with microorganism. We found that the most studies between MPs and microorganism are focused on bacterial in comparison with fungus and archaea in the past decade. Many microbes can accelerate the aging and degradation of MPs in soil. The abundance of MPs in indoor air is higher than that in outdoor air. The abundance of MPs in urban areas is greater than that in rural areas. The mechanism and process of MP degradation by microorganism mainly included deterioration, colonization, depolymerization, assimilation, and mineralization. Here, we review recent research on the interactions between microorganism (mainly bacteria and fungi) and MPs, and discuss characterization techniques used for revealing the MP degradation mechanisms of microorganism. However, there are several challenges associated with studies of the interactions between MPs and microorganism, and these have implications for the design of policies and the efficacy of ecological protection efforts implemented by governments worldwide.