Diseño de la variante mutante Q119Y-L117F de la enzima PETasa de Ideonella sakaiensis

Abstract

The massive accumulation of plastic waste poses a critical challenge to environmental sustainability. In 2022, global plastic production reached 400.3 million tons, with polyethylene terephthalate (PET) accounting for 6.2 percent of the total; however, only a limited fraction (35.5 million tons) was recycled, highlighting the need for efficient biocatalytic alternatives. PETase from Ideonella sakaiensis has emerged as a biotechnological alternative. Various studies have shown that modifications to key residues can improve its thermal stability and catalytic efficiency. In this study, the mutant variant IsPETaseQ119Y-L117F was constructed, whose plasmid was obtained through a specialized external organism. Subsequently, the recombinant enzyme was expressed and purified by affinity chromatography, ensuring its purity for functional analysis. Enzymatic activity was analyzed using commercially available PET pellets (post-consumer beverage bottles), with a reduction in mass recorded after incubation at 50 degrees Celsius for 9 days. The results obtained show that rational engineering of PETase can significantly improve its catalytic behavior and provides a scientific basis for continuing the design of more stable and efficient biocatalysts. This study thus contributes to the development of sustainable solutions aimed at the biodegradation of PET and the mitigation of the environmental impact associated with this polymer.