<![CDATA[Free α-amylase is readily inactivated at high temperatures and cannot be recovered after starch hydrolysis, which limits its industrial use. Hybrid supports can combine the advantages of their components, but a chitosan–silica gel 60 hybrid has not been reported for Aspergillus fumigatus α-amylase. This study aimed to compare the catalytic properties, thermal inactivation kinetics, and reusability of A. fumigatus α-amylase immobilized on silica gel 60, chitosan, and a chitosan–silica gel 60 hybrid. The enzyme was purified by (30–90)% ammonium sulfate fractionation and dialysis, increasing its specific activity from 702.23 to 3449.43 U/mg (4.9-fold). The hybrid, synthesized with glutaraldehyde as a cross-linker, showed the FT-IR bands of both components with wavenumber shifts, indicating their interaction. The enzyme was immobilized by physical adsorption at an optimum binding pH of 5.0 on all matrices. Immobilization raised the optimum temperature from 50 to 55 °C, increased KM from 3.48 to 4.62–5.80 mg mL−1, and decreased Vmax from 12.97 to 2.72–3.73 μmol mL−1 min−1. After 80 min at 60 °C, the purified enzyme retained 24.8% of its activity, whereas the enzyme immobilized on silica gel 60, chitosan, and the hybrid retained 77.3, 55.1, and 81.1%, respectively. The enzyme–hybrid had the longest half-life (260.85 min; a 6.5-fold increase), the highest free energy of inactivation (109.62 kJ mol−1), and the highest residual activity after six reuse cycles (57%). The chitosan–silica gel 60 hybrid is therefore a more effective support than either of its components for stabilizing and reusing α-amylase.]]>
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