Recent advances on the alpha-amylase immobilization using nanotechnology: Materials, methods, and applications

Alpha-amylase is a critical enzyme in biocatalysis, widely used in industries such as food, pharmaceuticals, textiles, and biofuel production. However, the widespread application of free alpha-amylase is hindered by its limited stability under harsh operational conditions, difficulty in recovery, and single-use nature. The immobilization of alpha-amylase onto nanomaterials has emerged as a powerful strategy to enhance its stability, activity, reusability, and overall operational efficiency. This comprehensive review provides an in-depth analysis of recent advancements in this field, systematically evaluating the types of nanomaterials employed, including metal oxides, carbon-based materials, polymers, and advanced hybrid nanocomposites. Key immobilization techniques such as physical adsorption, covalent binding, entrapment, encapsulation, and cross-linking are discussed, highlighting their respective mechanisms, advantages, and limitations. A detailed examination of recent literature demonstrates that nanoengineered immobilization significantly improves thermal stability, pH tolerance, storage stability, and reusability, often with enzymes retaining high activity over many cycles. Furthermore, this review explores the diverse applications of immobilized alpha-amylase across various industrial processes, from food processing and biofuel generation to textile desizing and pharmaceutical synthesis. Finally, current challenges including cost-effectiveness, scalability, toxicity concerns, and enzyme leaching are discussed, alongside future research directions involving artificial intelligence, green synthesis, and smart nanocarrier systems.