Stabilization of b-Glucuronidase by Immobilization in Magnetic-Silica Hybrid Supports

b-Glucuronidases are a class of enzymes that catalyze the breakdown of complex carbohydrates.<br> They have well documented biocatalytic applications in synthesis, therapeutics, and analytics that could<br> benefit from enzyme immobilization and stabilization. In this work, we have explored a number of<br> immobilization strategies for Patella vulgata -Glucuronidase that comprised a tailored combination of<br> biomimetic silica (Si) and magnetic nanoparticles (MNPs). The individual eect of each material on the<br> enzyme upon immobilization was first tested. Three dierent immobilization strategies for covalent<br> attachment on MNPs and dierent three catalysts for the deposition of Si particles were tested.<br> We produced nine dierent immobilized preparations and only two of them presented negligible<br> activity. All the preparations were in the micro-sized range (from 1299 52 nm to 2101 67 nm<br> of hydrodynamic diameter). Their values for polydispersity index varied around 0.3, indicating<br> homogeneous populations of particles with low probability of agglomeration. Storage, thermal,<br> and operational stability were superior for the enzyme immobilized in the composite material.<br> At 80 C dierent preparations with Si and MNPs retained 40% of their initial activity after 6 h of<br> incubation whereas the soluble enzyme lost 90% of its initial activity within 11 min. Integration of<br> MNPs provided the advantage of reusing the biocatalyst via magnetic separation up to six times with<br> residual activity. The hybrid material produced herein demonstrated its versatility and robustness as<br> a support for b-Glucuronidases immobilization.