Influence of reaction parameters in the polymerization between genipin and chitosan for enzyme immobilization

In this work, we studied the effect of some variables in the reaction between genipin and chitosan, to prepare a support for enzyme immobilization. Reaction temperature, pH, time and genipin concentration were evaluated for support activation and β-galactosidase from Aspergillus oryzae was used as the enzyme model. The immobilized enzyme was characterized by immobilization properties and kinetic parameters and by thermal and operational stability. It was found that support activation at alkaline pH (9.0), at 60 °C for 1 h, resulted in an activity recovery of 37.5%. The immobilized enzyme had a stabilization factor of 2.0 at 50 °C compared with the free enzyme. In batch process, the immobilized preparation kept 100% of its relative initial activity during 40 batches. This research shows, for the first time, a complete study about the parameters that affect the support activation process and the possible structure formed between genipin and chitosan.