Plastic pretreatment: The key for efficient enzymatic and biodegradation processes

In recent years, enzymatic degradation and biodegradation have attracted great interest in the recycling of plastic waste. Compared to other recycling techniques, they have numerous advantages such as mild reaction conditions both in terms of temperature and pressure and the prevention in the use of toxic solvents. The monomers formed during the degradation processes can result in chemicals with high added value, which can be purified and reused at an industrial level. Unfortunately, numerous factors, both environmental and related to polymer's nature, influence enzymatic degradation and biodegradation, making them very complex processes. An effective way to increase degradation consists in subjecting the plastic material to pretreatments of various kinds, capable of inducing modifications in the polymer and making it more susceptible to the action of microorganisms or enzymes. This review has the objective of analyzing the literature of the last 15 years, to identify the most efficient pretreatments on the base of the polymer's chemistry, also considering technical-economic aspects.