Immobilization of Baker's yeast invertase in PVA-alginate matrix using innovative immobilization technique

This paper presents an innovative technique of immobilizing Baker's yeast invertase using polyvinyl alcohol (PVA)-alginate matrix. Previous immobilization technique was improved by adding treatment solutions such as boric acid and sodium sulphate. PVA-alginate beads with four different compositions were investigated in terms of enzyme activity within the beads, immobilization yield, diffusion coefficient and also chemical and mechanical stability. The enzyme activity within the beads was also compared with the free enzyme activity. Finally, the microstructure of the beads was analyzed using SEM. Amongst others, the results revealed that the fabricated beads remained insoluble in aqueous solution owing to the innovative technique. In addition, beads produced from 12% (w/v) PVA concentration and 5% (w/v) boric acid possess at least 10% higher enzyme activity while those produced from 12% (w/v) PVA concentration and 7% (w/v) boric acid have at least 28% higher mechanical stability compared to the other formulations. (C) 2007 Elsevier Ltd. All fights reserved.