Emeson Farias Araujo Santos
Avaliação de inibidores de urease e desenvolvimento de sistema automatizado para triagem de compostos inibidores e identificação de microrganismos ureolíticos com aplicações agrícolas e clínicas
Resumo
The increasing use of nitrogen-based fertilizers and growing concern over the sustainability of agricultural systems make controlling urease activity a central challenge for improving nitrogen use efficiency and mitigating environmental impacts. Urease, by catalyzing the rapid hydrolysis of urea, is directly associated with nitrogen losses through ammonia volatilization and with imbalances in agricultural ecosystems, and also plays a significant role in pathogenic processes mediated by ureolytic microorganisms. Despite the use of commercial inhibitors such as NBPT, their effectiveness is often limited by instability under complex environmental conditions and by the inherent variability of natural systems. In this context, the thesis investigated the development and evaluation of new chemical and analytical strategies to control ureolytic activity in biological and environmental systems. Different structural classes were explored as potential sources of inhibitors, including organic, organometallic, and nanostructured systems, with emphasis on sulfur-containing compounds, phosphorus derivatives, and functional nanoparticles. The results demonstrate that inhibitory efficiency depends not only on the intrinsic affinity for the enzyme but is also strongly modulated by environmental complexity, particularly the presence of humic substances and soil matrices. The integration of kinetic, biophysical, and computational approaches revealed that inhibition mechanisms are multifactorial, ranging from reversible interactions at the active site to the stabilization of enzyme–ligand complexes, with direct effects on the conformational dynamics of urease. In parallel, it was demonstrated that enzymatic responses in real systems differ significantly from those observed under idealized conditions, reinforcing the need to evaluate them in environmentally relevant matrices. As an additional contribution, an automated analytical platform was developed to monitor urease activity and evaluate inhibitors reproducibly across different matrices, thereby reducing manual intervention and expanding analytical applicability in complex systems. Overall, the results of this thesis indicate that advances in urease control rely on integrating molecular innovation, mechanistic understanding under real-world conditions, and the development of automated analytical tools, thereby providing a solid foundation for future applications in sustainable agriculture and environmental monitoring.