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Abstract
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Nano-magnetic biocatalyst particles, lipase-immobilized chitosan-crosslinked magnetic nanoparticles (LCMNs) were prepared by a new approach integrated from magnetic nanoparticle preparation, in situ thin layer coating and crosslinking of chitosan, and enzyme immobilization method. Thin layer coating of magnetic (Fe3O4) by crosslinked chitosan nanoparticles were prepared by reacting FeCl3.6H2O and sodium acetate in ethylene glycol, followed by suspension cross-linking using citric acid on the hydroxyl and amine group of chitosan at neutral pH. The resulting nanoparticles were used to immobilize the lipase from Candida antarctica Lipase B by linking using glutaraldehyde. The particles in each step were characterized by Fourier transform infrared spectrometry (FT-IR), vibrating-sample magnetometer measurements (VSM), and transmission electron microscopy (TEM). The magnetic biocatalyst, LCMN was found to have high storage stability and reusability due to the tightly crosslinked structure of chitosan and covalent bond immobilization. LCMNs were used for the oligomerization of itaconic anhydride by ring opening esterification, and the results were compared with those from free lipase and commercial immobilized lipase. The molecular mass of the products obtained with the biocatalysts showed similar Mn profiles with 308–381. This process represents a green approach for the preparation of both biobased magnetic biocatalysts and functional oligo-esters, and can be applied for both the immobilization of other enzymes and the utilization of photo-curable functional esters as biobased functional materials.
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