Statistical optimization of chemical modification of chitosan-magnetic nano-particles beads to promote Bacillus subtilis MK1 α-amylase immobilization and its application

Abstract

B. subtilis MK1 α-amylase was successfully immobilized on chitosan-magnetic nano-particles using a method combining the advantages of both physical adsorption and covalent binding. The beads were chemically modified using polyethyleneimine (PEI) followed by glutaraldehyde (GA). Aminated beads by (PEI), activated beads by (GA), and immobilized enzyme on activated beads were characterized using FTIR. Morphological examinations of the beads surface before and after conjugation with the α-amylase enzyme were carried out using scanning electron microscope (SEM). Chemical modification parameters of the beads were optimized using response surface methodology based on central composite design. Statistical approach enhanced the immobilization yield (IY%) by 1.5-fold. The application of immobilized enzyme in the baking process enhanced dough-raising about 2.3-fold and can be reused for 5 cycles with 100% activity.