Immobilization of α-amylase onto Magnetic Nanomaterials: Process Optimization and Evaluation of Biocatalytic Activity

Abstract

Food industry is one of the most important industries in modern society and provides a wide range of products for human need. However, the perishability of crop and food products, results in the generation of significant quantities of food waste. Potato peel waste (PPW) as zero value byproduct generated from food processing industries contains large quantity of starch, non-starch polysaccharides, lignin, protein and lipids. As starch is high yield feedstock, requires enzymatic hydrolysis into reducing sugar before further processing. α-amylase, enzyme cleaves glycosidic linkages in starch and yields dextrins and oligosaccharides. In this work, α-amylase was immobilized onto the dopamine functionalized magnetic halloysite nanotube via Schiff base reaction. The ultimate aim was to develop a nanobiocatalysts (NBC) for efficient starch hydrolysis and determine its industrial capability. The synthesis and functionalization of magnetic carrier for immobilization were examined by UV-visible spectroscopy, FTIR, VSM and FE-SEM. A high enzyme loading of 185.52 mg/g of support matrix was achieved. The immobilized α-amylase displayed optimal activity at pH 6.5 and temperature 50 ℃. Furthermore, the pH and thermal stability of the immobilized enzyme indicates improvement as compared to its free counterpart. The immobilized enzyme had also been demonstrated to be capable of being reused for 10 cycles with 56.7% retained activity. In addition to that, even after storage time of 30 days the NBC retained almost 64.8% of initial activity.