Characterization of the Immobilized Fructosyltranferase from Rhodotorula sp.

The fructosyltransferase from Rhodotorula sp. recovered from a fermented medium, by precipitation was immobilized by adsorption onto niobium ore. Considering the biocatalyst system, the activity/pH profile moved towards more alkaline values as compared to the free enzyme system, indicating that the support affected the charge distribution between the enzyme and the support. The immobilized enzyme showed high activity and good stability at pH values of 4.5 and 6.0. The biocatalyst half-lives at 48 degrees C and pH values of 4.5 and 6.0 were 32 and 72 days, respectively. The kinetics for the immobilized system corresponded to that of substrate inhibition. The synthesis of fructooligosaccharides from 50% sucrose solutions was carried out in batch stirred reactors and the conversion was about 58%, similar to that with the free enzyme. Based on the biocatalyst activity, stability and process yields, the system developed in this work can be considered suitable for application in large-scale bioreactors.