The aim of this work is to evaluate the performance of glucose oxidase (GO) (EC.1.1.3.4) adsorbed on DOWEX (R)-anionic resins in a continuous process using a membrane reactor coupled with a UF (cut-off of 100 kDa) or a MF (a pore diameter of 5 mu m) membrane. Tests with soluble GO were also performed. At 20-h steady-state-continuous operations (constant parameters: 30 degrees C, pH 5.5, 100rpm, 2.5 mM glucose, D = 6 h(-1) and 0.094 U of GO), the reaction rate (r) and the conversion glucose/gluconic acid yield (Y) differed according to the type of membrane coupled to the reactor and to the form of GO used. The highest r (3.64 mmol/h U) and Y of 79% were observed in the test carried out in a UF-membrane reactor using soluble GO, whereas the highest Y (90%) and r of 2.37 mmol/h U occurred in the test carried out in a MF-membrane using immobilized GO. No leakage of enzyme from the support was detected. (c) 2006 Elsevier lnc. All rights reserved.