Immobilization of amyloglucosidase from SSF of Aspergillus niger by crosslinked enzyme aggregate onto magnetic nanoparticles using minimum amount of carrier and characterizations

•Amyloglucosidase from solid state fermentation extracts was directly immobilized.•Crosslinked enzyme aggregate onto magnetic nanoparticles was prepared.•High recovery (∼93% activity) into immobilized enzyme using 14 times less carrier.•Immobilized enzyme showed enhanced substrate affinity, stability, reusability.•Procedure expected to reduce the cost of starch hydrolysis process.

Immobilizations of enzymes are done for operational stability, recovery and re-use of the enzymes and easy separation of products. Amyloglucosidase (AMG) obtained from solid state fermentation (SSF) of Aspergillus niger was directly immobilized by novel technique of crosslinked enzyme aggregate onto magnetic nanoparticles. AMG was covalently linked to the magnetic nanoparticle (MNP) to form a monolayer of AMG (MNP–AMG), followed by crosslinked aggregates with free AMG (which was not immobilized) to yield MNP with high enzyme loading (MNP–AMGn). Under optimized conditions, very high recovery (92.8%) of enzyme activity was obtained in MNP–AMGn using 14 times less carrier compared to the quantity of carrier required by conventional method. MNP–AMGn showed enhanced affinity for substrate, thermal stability, storage stability and reusability.

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