In this study, alpha-amylase immobilized onto CaO-Fe3O4 using xylan aldehyde as a linking molecule was characterized for its hydrolysis of glycogen from Synechocystis sp. PCC 6803. CaO blended with Fe3O4 can improve the binding efficiency and specific activity. The oxidised birchwood xylan was a linking molecule for enzyme and metal nanoparticles. The analysis of the immobilized enzyme by FTIR, SEM-EDS and XRD confirms the linkage between the enzyme and nanoparticle (CaO-Fe3O4) with the assistance of xylan aldehyde. Incorporation of CaO and xylan aldehyde along with the magnetic Fe3O4 improved the overall binding efficiency and residual activity of the enzyme. The metal nanoparticle linked a-amylase showed a significant increase in the hydrolysis of glycogen. Moreover, the immobilized enzyme was highly stable under various temperatures and pHs and could be reused with an estimated half life of 138.6 h based on 7 cycles experiments. Under optimized conditions, the glucose yield observed was 89% of theoretical maximum. Overall results indicate that the improved enzyme performance is ascribed to the combined action of metal nanoparticle and enzyme.