Microbial Degradation of Microplastics in Aquatic Ecosystems: A New Frontier in Environmental Bioremediation

Abstract

Microplastics, which are defined as plastics that are below 5 mm in their dimension, have become widespread pollutants to the marine ecosystem, with dire consequences to marine creatures, ecological balance, as well as human health. The problem of accumulating synthetic polymers has become a burning issue all over the globe due to the recalcitration nature of these polymers. Microbial degradation has become a trend in recent years as one of the promising environmentally friendly methods to reduce microplastic pollution. Several bacteria, fungi and actinomycetes have shown themselves capable of colonizing, biofilm forming and enzyme degrading polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP) and polystyrene (PS). In this paper the authors discuss the processes of degradation of microbes, such as enzyme hydrolysis, oxidation, and fragmentation, as well as those environmental conditions that affect the degradation rate. Major microbial genera examined in the study included Pseudomonas, Bacillus, Rhodococcus, Aspergillus, and Ideonella sakaiensis whose enzymes are PETase and MHETase, which depolymerize plastics. Besides, the paper also assesses the possibility of using microbial consortia, genetic engineering and bioreactor-based methods to achieve large-scale bioremediation. The findings point to microbial degradation as a potential sustainable, low-cost alternative to physical and chemical degradation, although there are the problems of scalability and rate of degradation. The research arrives at the conclusion that the use of biotechnology and ecosystembased management to increase microbial activity can help in the world effort to alleviate plastic wastes to a greater extent.