**4.4 High sucrolytic activity by invertase immobilized onto magnetic diatomaceous earth nanoparticles**

The purpose of this work was to produce magnetic diatomaceous earth nanoparticles for invertase immobilization (mDE-APTES-invertase) using an easy and low-cost method that could offer high sucrolytic activity [22]. To obtain the results of high residual specific activity (92.5%), an experimental design was made with the objective of achieving the best immobilization conditions. This activity was able to be 2.42 times higher than other derivatives reported in the literature. The thermal and storage stability of the immobilized invertase was verified, and after 120 days of storage, the enzymatic derivative retained 80% of the activity, whereas the free enzyme lost practically all the activity. After ten reuses mDE-APTES-invertase retained 60% of residual activity. Considering the ease of obtaining the matrix and its efficiency, this nanocomposite proves promising to immobilize invertase from different origins and other biomolecules.
