A research team at MIT and the Woods Hole Oceanographic Institution has engineered bacteria capable of efficiently degrading PET plastic, the most common type of single-use plastic waste, in marine conditions. Previous plastic-eating enzymes developed for this purpose required elevated temperatures and pH conditions far from ocean environments, limiting their practical application. The new organisms incorporate novel enzyme variants identified through directed evolution that function effectively in cold, salty water.
Laboratory and controlled mesocosm testing shows the engineered bacteria can degrade small PET fragments at rates ten times faster than unaided natural microbial communities. Field application faces significant technical and regulatory hurdles including ensuring that engineered organisms do not outcompete native marine microbes in ways that disrupt ocean ecosystems. The research team is proposing contained bioreactor deployment at plastic accumulation hotspots as an initial application that would avoid open ocean release concerns.
