Reciclagem enzimática do PET para reuso de monômeros

Abstract

As science and technology improved, it was possible to use intelligent packaging for food preservation, thus making storage methods more efficient and lighter with the use of polymers such as poly(ethylene terephthalate) (PET). However, these synthetic polymers have low degradability in nature which generates a huge amount of solid waste annually due to the rapid and single-use of these packages. Hence, this work aims to review the literature on processes involving PET recycling focusing on the application of enzymes as catalysts and the reuse of ethylene glycol (EG) and terephthalic acid (TA) monomers from the depolymerization of PET for the reaction of biossintesis of Poly-alkanoates (PHAs) using Pseudomonas sp. The traditional methods of recycling are mechanical, energetic and chemical, these methods were created to reduce the generation of solid waste and allow the use of these materials for a longer time. On the other hand, in the current methods that are being researched, there is the enzymatic recycling of PET through two enzymes, PETase and MHET hydrolase. When combined can form EG and TA, which are products of PET depolymerization, thus allowing the obtaining of monomers and reducing the need to use fossil sources. Furthermore, recent studies show the formation of PHAs from Pseudomonas sp. in a low nitrogen environment. This is a class of biodegradable polymers with thermoplastic or elastomeric properties depending on their molar mass and branches. Additionally, EG and TA can be used as substrates to produce PHAs to be incorporated into the microorganism's primary metabolic pathway and stored in vesicles. Consequently, it is possible to reduce the generation of solid waste from packaging produced by non-biodegradable polymers such as PET and still allow the production of PHAs, which is a polymer with greater added value, so there is an eminent appreciation of the enzymatic recycling method and reuse of monomers.