A review on microbial bioremediation of polyethylene terephthalate microplastics

Microplastics (<5 mm size) continue to be a disruptor in the ecosystem being omnipresent in the various spheres of the earth. While there have been various approaches for their degradation, biological approaches continue to be an emerging technology owing to their reduced stress on the environment and energy efficiency. This review paper encompasses the problems created by these microplastics and specifically focuses on polyethylene terephthalate (PET) that are widely used in the packaging and textile industries. This review paper highlights the various microorganisms used to degrade PET and optimum conditions in which PET degradation was carried out. PET is converted to MHET (mono (2-hydroxyethyl) terephthalic acid) by extracellular PETase, which is subsequently transferred into the periplasmic region of microorganisms by outer membrane anchored MHETase, which transforms MHET to terephthalic acid and ethylene glycol. Factors affecting PET degradation like temperature, pH, crystallinity and environment have also been analyzed.