Authors: Yolanda Osuna José Sandoval Hened Saade Raúl G López José L Martinez Edith M Colunga Gabriela de la Cruz Elda P Segura Fernando J Arévalo María A Zon Héctor Fernández Anna Ilyina
Publish Date: 2015/03/11
Volume: 38, Issue: 8, Pages: 1437-1445
Abstract
Aspergillus niger lipase immobilization by covalent binding on chitosancoated magnetic nanoparticles CMNP obtained by onestep coprecipitation was studied Hydroxyl and amino groups of support were activated using glycidol and glutaraldehyde respectively Fourier transform infrared spectrometry highresolution transmission electron microscopy and thermogravimetric analysis confirmed reaction of these coupling agents with the enzyme and achievement of a successful immobilization The derivatives showed activities of 3095 ± 20 and 2662 ± 28 U g support−1 for the CMNP treated with glutaraldehyde and with glycidol respectively Immobilization enhanced the enzyme stability against changes of pH and temperature compared to free lipase Furthermore the kinetic parameters K m and V max were determined for the free and immobilized enzyme K m value quantified for enzyme immobilized by means of glutaraldehyde was 17 times lowers than for free lipase High storage stability during 50 days was observed in the immobilized derivatives Finally immobilized derivatives retained above 80 of their initial activity after 15 hydrolytic cycles The immobilized enzyme can be applied in various biotechnological processes involving magnetic separation
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