Enzymes encapsulation within calcium alginate-clay beads: Characterization and application for cassava slurry saccharification

Multi-enzymes (alpha-amylase, glucoamylase and cellulase) were successfully encapsulated in calcium alginate-clay beads to hydrolyze cassava roots for glucose production. Under the optimal conditions (2% clay solution and 0.2 M CaCl2), the loading efficiency and the immobilization yield of enzymes were calculated to be 97.07% and 52.14%, respectively. The calcium-alginate-clay beads have been analyzed using Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-Ray (EDX). FTIR results showed that asymmetric and symmetric COO-and OH-group shifted to 1621, 1419 and 3324 cm(-1) and proved strong interaction between alginate and clay of the beads. Observation under FESEM showed that the beads have a rough surface and the enzymes were successfully encapsulated in the beads. The presence of the clay elements in the beads was confirmed by EDX analysis where the beads consist of 13.97% C, 43.69% O, 28.96% Ca, 6.46% Al and 6.91% Si. The beads were later used for the saccharification of cassava slurry into glucose. Results showed that the process was successful and the encapsulated enzymes in calcium alginate-clay beads have enhanced the enzymes reusability in the process compared to pure alginate beads where it retained 51.77% of its activity after seven hydrolysis cycles. (C) 2013 The Authors. Published by Elsevier Ltd.