Kinetics and bioreactor studies of immobilized invertase on polyurethane rigid adhesive foam

A new support, polyurethane rigid adhesive foam (PRAF), which can be used to cover internal surface of metallic tubes, was used to immobilize invertase for application in an enzymatic bioreactor. The kinetic parameters were: K-m - 46.5 +/- 1.9 mM (PRAF-invertase) and 61.2 +/- 0.1 mM (free enzyme) and V-max 42.0 +/- 4.3 U/mg protein/min (PRAF-invertase) and 445.3 +/- 24.0 U/mg protein/min (free invertase). The PRAF-invertase derivative maintained 50.1% of initial activity (69.17 U/g support) for 8 months (4 degrees C) and was not observed microbial contamination. The bioreactor showed the best production of inverted sugar syrup using up-flow rate (0.48 L/h) with average conversion of 10.64 +/- 1.5% h(-1) at feeding rate (D) of 104 h(-1). The operational inactivation rate constant (k(opi)) and half-life were 1.92 x 10(-4) min(-1) and 60 h (continue use). The PRAF spray support looks promising as a new alternative to produce immobilized derivatives on reactor surfaces. (C) 2010 Elsevier Ltd. All rights reserved.