Microbial Consortium-Mediated Degradation of Polyethylene Terephthalate in Orthodontic Aligners: A Comprehensive Review.

In this review, we critically assess microbial consortia-mediated biodegradation of polyethylene terephthalate (PET) used in orthodontic aligners as a means to address the environmental problems arising from biomedical plastic waste. PET's chemical stability and high crystallinity provide sufficient durability for clinical efficacy; however, natural degradation is hindered in the resulting environmental accumulation. Currently, the conventional disposal methods can lead to toxic emissions, so they have to be kept in the dark in terms of innovations that reduce or eliminate them. These microbial consortia utilize hairy dynamics of synergistic enzymatic activities, that is, PETase and MHETase, to degrade PET into assimilable monomers, with the potential to be a bioremediation strategy. In this paper, we summarize current analytical methodologies to assess degradation, present molecular tools to elucidate microbial community dynamics, and discuss biotechnological strategies to enhance enzymatic efficiency and process scale-up potential. Slow degradation rates, material complexity, and environmental variability are identified as challenges. Advances in enzyme engineering, bioaugmentation, and bioreactor design associated with biodegradation performance are reviewed, and future research directions that will enhance the ecosystemic performance of microbial consortia for eco-friendly and effective management of PET waste from orthodontic aligners within the framework of a circular bioeconomy are pointed out.