Abstract
Immobilization has gained importance in industrial biotechnology as an efficient approach for modifying the characters ensuring the reusability of biocatalysts. The current study focuses on the potential application of entrapment and cross-linking techniques to immobilize the lipase from Serratia marcescens VT 1 (SMVT 1). Purified SMVT 1 lipase was immobilized by entrapment onto calcium alginate beads and cross-linking with glutaraldehyde. The effect of different factors affecting entrapment and cross-linking was determined. Further, the immobilized lipase was subjected to characterization and reusability studies. The calcium alginate entrapment and glutaraldehyde cross-linking resulted in an immobilization yield of 65.72% and 77.19% respectively. Optimal conditions for entrapment were 3% sodium alginate, 3 M calcium chloride (CaCl2), and an immobilization time of 45 min, while, for cross-linking it was 0.4% glutaraldehyde and a cross-linking time of 45 min. Characterization and reusability studies highlighted cross-linking as superior with enhanced activity and stability at higher temperatures, a shift in optimum pH to 8, good stability in basic pH, and 58.5% residual activity after eight cycles of reactions. Fourier transform infrared spectroscopy analysis provided insights into the bond formations during calcium alginate entrapment and glutaraldehyde cross-linking. Cross-linking was identified as an ideal mode of immobilization for SMVT 1 lipase.
Keywords: Calcium alginate, Cross-linking, Glutaraldehyde, Immobilization, Lipase, Serratia marcescens.