Characterization of Immobilized Carrageenase on Superparamagnetic Nanoparticles for Oligosaccharide Preparation

kappa-Carrageenase from Pseudoalteromonas carrageenovora was immobilized onto carboxyl functionalized magnetite nanoparticles (CMNPs) by using glutaraldehyde as the coupling agent. The CMNPs and immobilized kappa-carrageenase exhibited distinct magnetic response and superparamagnetic properties, as determined by vibrating sample magnetometry. X-ray diffraction indicated that the magnetic effect was attributable to Fe3O4. Analyses by scanning electron microscopy and transmission electron microscopy showed that the mean diameter of the CMNPs and the immobilized kappa-carrageenase was 15 nm. Zeta potential and particle size analysis of the CMNPS and the immobilized kappa-carrageenase showed excellent dispersion in deionized water. The immobilized enzyme activity and the recovery rate were determined to be 326.0 U kg(-1) carrier and 46.9% respectively. The immobilized kappa-carrageenase was used to convert kappa-carrageenan into kappa-carrageenan oligosaccharide. Hydrolysis products were identified by electrospray ionization time-of-flight mass spectrometry as disaccharides and tetrasaccharides. The results indicated that the immobilized kappa-carrageenase can be used in the preparation of carrageenan oligosaccharides.