Fructooligosaccharides synthesis by highly stable immobilized β-fructofuranosidase from Aspergillus aculeatus

The enzymatic synthesis of fructooligosaccharides (FOS) was carried out using a partially purified beta-fructofuranosidase from the commercial enzyme preparation Viscozyme L. Partial purification of beta-fructofuranosidase from Viscozyme L was done by batch adsorption using ion-exchange resin DEAE-Sepharose, showing a 6-fold increase in specific activity. The biocatalyst was then covalently immobilized on glutaraldehyde-activated chitosan particles. Thermal stability of the biocatalyst was evaluated at 50 degrees C and 60 degrees C, being around 100 times higher at 60 degrees C when compared to the free enzyme. The immobilized biocatalyst was reused 50 times for FOS production (100 min per batch at 50 degrees C and pH 5.5) without significant loss of activity. The average yield (grams of FOS per grams of initial sucrose) was 55%. The immobilization process combined with partial purification method resulted in a derivative with activity of 1230 U-t/g, which is among the best for FOS production. (C) 2013 Elsevier Ltd. All rights reserved.