Hydrolysis of soluble starch using Bacillus licheniformis α-amylase immobilized on superporous CELBEADS
Abstract
In the present work, indigenously prepared rigid superporous (pore size of approximately 3 μm) cross-linked cellulose matrix (CELBEADS) has been used as a support for the immobilization of Bacillus licheniformis α-amylase (BLA). Optimum pH and temperature, and Michaelis–Menten constants were determined for both free and immobilized BLA. Immobilized BLA was observed to produce a different saccharide profile than free BLA at any value of dextrose equivalent. It was observed that pH, temperature, and initial starch concentration has a significant effect on the saccharide profile of starch hydrolysate produced using immobilized BLA in the batch mode, whereas the ratio of concentration of enzyme units to initial starch concentration has no influence on the same. Hence immobilized BLA can be used as an additional tool for production of maltodextrins with different saccharide profiles. Immobilized BLA has better thermostability than free BLA. Immobilized BLA was found to retain full activity even after eight batches of hydrolysis, each of 8 h duration at 55 °C and 90 mg/mL initial starch concentration. A semiempirical model has been used for the prediction of saccharide composition of starch hydrolysate with respect to time.