 Oxo-degradable plastics cannot be classified as biodegradable under American and European standards because they take too long to break down and leave plastic fragments not capable of being consumed by microorganisms.Although intended to facilitate biodegradation, oxo-degradable plastics often do not fragment optimally for microbial digestion.With rising concern for environmental ramifications of plastic waste, researchers have been exploring the application of genetic engineering and synthetic biology for optimizing biodegradable plastic production.