The increasing prevalence of emerging pollutants in aquatic environments poses serious risks to both public health and ecosystem sustainability. Among these contaminants, endocrine-disrupting compounds, such as bisphenol A, are of particular concern due to their ability to interfere with hormonal systems even at trace concentrations. Conventional wastewater treatment plants are unable to completely remove these pollutants, highlighting the need for innovative and sustainable remediation strategies. In this context, enzymes such as laccase have attracted attention due to their ability to oxidize and eliminate endocrine disruptors, including bisphenol A. However, the direct application of free enzymes in large-scale systems is limited by challenges related to stability, recovery, and reuse. To overcome these limitations, this work explored the covalent immobilization of laccase onto superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with epoxy groups.

For that purpose, different immobilization incubation times and acetate buffer concentrations were evaluated to optimize enzyme loading and catalytic activity, which was monitored by UV–Vis spectroscopy. Dynamic light scattering measurements showed an increase in particle size upon enzyme addition, suggesting successful attachment of laccase to the nanoparticle surface. Immobilization was achieved with increasing enzyme concentrations, though with modest yields (~20%) as quantified using the BCA assay. Alternative buffers (Tris-HCl, phosphate, borate) were tested, although the acetate buffer proved to be more suitable.

Future work will be focused on assessing the nanoparticles performance in removing endocrine disruptors. These findings contribute to advancing sustainable water treatment technologies by integrating enzymatic efficiency with nanomaterial-based recovery strategies.