Simple adsorption of TA on PP_PDA membranes led to important leaching (entry 9 and 12). However, using the covalent immobilization approach with GDE, TA leaching was significantly reduced (Table , compare HeWT_PP2 and TsRTA_PP2 with HeWT_PP1 and TsRTA_PP1, respectively). This highlights the beneficial role of the epoxy functions, able to immobilize the TA via covalent coupling . Interestingly, TA_PP2 also showed greater immobilization yield and specific activity with respect to TA_PP1 biocatalyst. Such enhanced specific activity obtained with GDE-immobilized TAs has already been observed in literature, and it was attributed to the hydrophilic and appropriate length of the epoxy linker-arm .