Enzymatic recycling of polyesters

Nowadays, the incorrect disposal of plastic and bioplastic waste has become one of the major pollution problems worldwide. Due to their chemical properties, these polymers are recalcitrant to degradation under normal environmental conditions, causing their accumulation in ecosystems. The main objective of this thesis project is to evaluate the industrial feasibility of the enzymatic recycling of polyesters as a sustainable approach to counteract the lack of management systems for these materials, thereby promoting a circular economy. To achieve this, the enzymatic degradation of PLA using the commercial enzyme proteinase K was optimized by analyzing temperature, pH and enzymatic concentration as operating parameters, while investigating also the reaction kinetics. Furthermore, this study aims to assess the potential of scaling up the PLA degradation process using proteinase K for industrial applications, increasing the reaction volume and reducing operating costs. In parallel, to meet the need for a sustainable industrial-scale enzyme supply, E. coli BL21(DE3) competent cells were transformed, using molecular biology techniques, with the plasmid pET-26b(+) to independently express and produce a cutinase capable of degrading both PLA and PCL. Keywords: recycling, enzymes, polyesters, PLA, molecular biology.