Preparation and characterization of chitosan membranes by using a combined freeze gelation and mild crosslinking method.
When gelification is performed by freezing-thawing repeated cycles, the resultant gel-like polymer systems are called cryogels. This work aims to assess the effect of the addition of glutaraldehyde and 18 Crown Ether-6 on surface properties and protein loading of dried chitosan cryogel films. Residual water content of treated chitosan membranes ranged between 11.93 and 13.86%, while their water activities vary from 0.5 to 0.7 (measured from 4 to 60 degrees C). Based on thermal data, water evaporation peak and degradation temperatures of chitosan membranes shifted to a higher temperature for crosslinked samples. X-ray diffractograms provide high values of crystallinity for all the samples (70.67-92.86%), the highest value being for the glutaraldehyde-treated membrane. Candida rugosa lipase can be immobilized successfully on chitosan membranes. Lipase immobilized on glutaraldehyde-crosslinked chitosan yielded the highest efficiency in terms of total coupled protein and protein loading efficiency.
Departamento de Física y Química, Universidad Nacional de Colombia-Sede Manizales, Plantas Piloto de Biotecnología y Agroindustria, Campus La Nubia, Manizales AA127, Colombia. corregoa@unal.edu.co
Carlos E
CE
Orrego
Jesús S
JS
Valencia
D002152:Calorimetry, Differential Scanning; D002175:Candida / Q000201:enzymology; D048271:Chitosan / Q000737:chemistry*; D005615:Freezing; D005782:Gels; D008049:Lipase / Q000737:chemistry; D008567:Membranes, Artificial; D018625:Microscopy, Atomic Force; D014961:X-Ray Diffraction
D005782:Gels; D008567:Membranes, Artificial; D048271:Chitosan; D008049:Lipase