Immobilization of β-fructofuranosidase for the synthesis of lactosucrose

Abstract:

[Objective] We explored an appropriate resin to immobilize β-fructofuranosidase (β-FFase) to produce lactosucrose. [Methods] β-FFase was immobilized onto nine adsorption and ion-exchange resin, to select the best resin for immobilization. To improve immobilization efficiency, β-FFase was immobilized onto the resin modified by polyethylenimine (PEI). A series of immobilization conditions were optimized. The stability of the immobilized enzyme and lactosucrose synthesized by the immobilized enzyme were also explored. [Results] Ion-exchange resin D311 was excellent for β-FFase immobilization. Immobilization efficiency was improved apparently when D311 resin activated by PEI. The immobilized conditions were as follows: 2% PEI, 103 U/g resin, 25 °C, pH between 6.0 and 8.0, 8 h adsorption time. Under these conditions, the immobilized enzyme activity reached 57 U/g, and immobilized yield was 55.3%. Using the immobilized β-FFase to hydrolysis 1 mol/L sucrose, the immobilized enzyme can be used for 15 times with no apparently activity loss, and approximately 137 g/L lactosucrose was synthesized within 8 h. [Conclusion] β-FFase immobilized onto the resin modified by PEI showed a good operational stability and a high productivity of lactosucrose.

Key words:β-Fructofuranosidase, D311 resin, Immobilization, Polyethylenimine, Lactosucrose