Recent advances in biodegradation of emerging contaminants - microplastics (MPs): Feasibility, mechanism, and future prospects

Plastics have become an essential part of life. When it enters the environment, it migrates and breaks down to form smaller size fragments, which are called microplastics (MPs). Compared with plastics, MPs are detrimental to the environment and pose a severe threat to human health. Bioremediation is being recognized as the most environmentally friendly and cost-effective degradation technology for MPs, but knowledge about the biodegradation of MPs is limited. This review explores the various sources of MPs and their migration behavior in terrestrial and aquatic environments. Among the existing MPs removal technologies, biodegradation is considered to be the best removal strategy to alleviate MPs pollution. The biodegradation potential of MPs by bacteria, fungi and algae is discussed. Biodegradation mechanisms such as colonization, fragmentation, assimilation, and mineralization are presented. The effects of MPs characteristics, microbial activity, environmental factors and chemical reagents on biodegradation are analyzed. The susceptibility of microorganisms to MPs toxicity might lead to decreased degradation efficiency, which is also elaborated. The prospects and challenges of biodegradation technologies are discussed. Eliminating prospective bottlenecks is necessary to achieve large-scale bioremediation of MPs-polluted environment. This review provides a comprehensive summary of the biodegradability of MPs, which is crucial for the prudent management of plastic waste.