Reducing CO2 emissions by developing alternative energy resources to fossil fuels is highly recommended. Biomass has been receiving much attention as a renewable energy source and studies on the conversion of biomass to high-performance and easy-to-use fuel or energy are being strongly supported. Polyethylene-terephthalate (PET), a saturated polyester of terephthalic acid (TPA) and ethylene glycol (EG), was widely used in daily life such as in drink bottles, so treatment of waste PET becomes very important. PET is a semicrystalline polyester with excellent thermal and mechanical properties, very vulnerable to chemical degradation. The main PET chemical recycling processes that reached commercial maturity are glycolysis and methanolysis. The PET fibers were completely hydrolyzed under alkaline conditions. Aminolysis is the reaction of PET waste with different amines to yield the corresponding diamides TPA and EG. PET recycling become economically viable when applied to large volumes such as industrial polymer waste or in the case of manufacturing special products of low or medium tonnage.