Fructooligosaccharides synthesis by highly stable immobilized β-fructofuranosidase from Aspergillus aculeatus
The enzymatic synthesis of fructooligosaccharides (FOS) was carried out using a partially purified-fructofuranosidase from the commercial enzyme preparation Viscozyme L. Partial purification of-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 immobilizedon glutaraldehyde-activated chitosan particles. Thermal stability of the biocatalyst was evaluated at 50◦Cand 60◦C, being around 100 times higher at 60◦C when compared to the free enzyme. The immobilizedbiocatalyst was reused 50 times for FOS production (100 min per batch at 50◦C and pH 5.5) withoutsignificant loss of activity. The average yield (grams of FOS per grams of initial sucrose) was 55%. Theimmobilization process combined with partial purification method resulted in a derivative with activityof 1230 Ut/g, which is among the best for FOS production.