Harnessing Microbial Plasmids for Plastic Biodegradation and Environmental Sustainability

This literature review examines the role of microbial plasmids in plastic biodegradation and their potential for environmental sustainability. Plastic pollution from polymers such as polyethylene (PE), polyethylene terephthalate (PET), and polypropylene (PP) persists globally, while conventional disposal methods, including landfilling and incineration, remain inefficient and environmentally harmful. Microbial biodegradation mediated by plasmids offers a promising alternative, as plasmids act as mobile genetic elements that transfer plastic-degrading genes and enhance microbial adaptability in contaminated environments. Key plasmid-encoded enzymes, including PETase and MHETase, are central to breaking down plastics, with horizontal gene transfer mechanisms such as conjugation, transformation, and transduction enabling their spread across microbial populations. Laboratory studies have demonstrated the successful use of engineered plasmids in Escherichia coli and Pseudomonas species, though challenges remain in biosafety, genetic containment, and large-scale application. Knowledge gaps include a limited understanding of plasmid stability in natural ecosystems, uncertainty regarding long-term degradation efficiency, and insufficient regulatory frameworks for the use of engineered plasmids. By synthesizing findings across microbiology, synthetic biology, and environmental policy, this review affirms that while plasmid-based strategies present considerable promise, their translation into scalable solutions will depend on integrated scientific validation and well-defined policy frameworks.