Performance of invertase immobilized on glass-ceramic supports in batch bioreactor

Invertase was covalently immobilized on glass-ceramic support (G(S) obtained from coal fly ashes (CFA) with polyvinyl pyrrolidone (PVP) and magnesium stearate added as temporary additive. The GCS samples containing Pb(CH3COO)(2), (GCSPb) or ZnSO4 (GCSZn) were obtained in several sintering temperatures (1000-1200 degrees C) and times (1-3 h). The apparent values of porosity, water absorption, density and uniaxial compressive strength were studied by factorial design and morphological differences by scanning electron microscope. The best covalent immobilized invertase derivative was on GCSZn (1200 degrees C/1 h) with 4398 +/- 59.75 U/g GCS. However, 95.83% of immobilized invertase activity was obtained using an economical protocol with concentration of 0.636 mM 3-aminopropyltriethoxy silane (3-APTES) and 0.576 mM glutaraldehycle. The GCSZn-invertase derivative retained 100% of initial activity after nine reuses (5476.19 +/- 155.49 U/g GCSZn). The CFA showed to be a promising biotechnological alternative as immobilization support for production of invert sugar and may be for other industrial enzymes. (C) 2012 Elsevier B.V. All rights reserved.