DEVELOPMENT OF HYPERACTIVATED BIOHYBRID MEMBRANES FOR ORGANOPHOSPHATE PESTICIDES DEGRADATION

The harmful effects of pesticides on humans and environment have led researchers to develop sustainable methods to inactivate them. The use of immobilized extremophilic enzymes seems very promising for the development of biocatalytic systems capable of degrading pesticides [1], but a deep understanding of the factors affecting the performance of the conjugated process and the development of strategies to further improve their catalytic properties are crucial. The aim of this study was to characterize the activity and stability of a thermophilic phosphotriesterase immobilized on polymeric membrane in the presence of cationic (CTAB) and anionic (SDS) surfactants to produce hyperactivated biocatalytic membranes for pesticide degradation and to understand the main mechanism that promotes activity enhancement. The effects of surfactant concentrations on enzyme activity, stability, secondary structure, aggregation, and kinetic parameters (KM, Kcat, Kcat/KM) were investigated. The results showed that the activity of immobilized phosphotriesterase toward the pesticide paraoxon was greatly increased in the presence of SDS and CTAB (about 90% and 80%, respectively), because they can affect the performance of the biocatalytic membrane by inducing conformational changes in the secondary structure of the enzyme and in its aggregation state (CTAB) or by increasing the affinity of the enzyme for the substrate (SDS).