Evaluation of enzymatic activity of commercial inulinase from Aspergillus niger immobilized in polyurethane foam

The objective of this work was to evaluate the stability of the activity of commercial inulinase from Aspergillus niger immobilized in polyurethane foam. The activity of the enzyme was measured in the hydrolysis reaction of both sucrose and inulin at 50 degrees C and pH 5.5. The enzyme reuse was evaluated during 59 days and 29 reuse cycles. The inulinase immobilized in polyurethane kept 49.7% and 49.4% of its initial activity during 1008 h and 24 reuse cycles for sucrose and inulin, respectively. In this work, enzyme immobilization was accomplished together with the formation of the polyurethane foam, which is an interesting characteristic, differing from several works found in the literature. Taking into account the promising results obtained, the low cost of the immobilization support employed and the whole technique developed, this work may comprise an innovative contribution. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.