Immobilization of Enzymes into a Polyionic Hydrogel: ChitoXan

Abstract

Three enzymes were immobilized onto polyionic hydrogel, ChitoXan, obtained by complexation between chitosan and xanthan. The biocatalysts used were two proteases (protease type XIX from Fungal d’Aspergillus sojae and the trypsin type II.S from Porcine Pancreas) and a lipase (lipase Type VII from Candida rugosa). The immobilization efficiencies and the relative activities were investigated for these enzymes. The immobilization efficiencies changed with each enzyme and varied between 53 and 80%. Good relative activities were found for the lipase Type VII from Candida rugosa and the protease type XIX from Fungal d’Aspergillus sojae. For the latter, the influence of several factors were studied: molarity of the storage buffer, storage temperature and time of hydrogel, and the enzyme concentration. For the immobilized lipase, hydrolysis of olive oil in aqueous and organic media has been compared. This study confirmed that the lipase modified the external and internal structure of the hydrogel from fibrillar to the formation of globular structures in the presence of lipases.

Supramolecular Polymer Networks: Preparation, Properties, and Potential

“…Stable hydrogels exhibiting a fibrillar structure, as observed by electron microscopy, were formed that contained very high amounts of water (up to 95 %). Dumitriu investigated the structure-property relationship of these materials by variation of the precursorpolymer composition and found the mechanism of gelation to be based on coacervation [256]. Furthermore, electron microscopy revealed the formation of fibrillar structures, which makes this system interesting for biomedical applications such as drug delivery and cell encapsulation.…”

Isothermal titration calorimetry study of the polyelectrolyte complexation of xanthan and chitosan samples of different degree of polymerization

“…The interaction between xanthan and chitosan has previously been studied with regard to both polyelectrolyte complexes 21,22 and multilayers, 23 and these two polymers have also been used to form hydrogels, [24][25][26] for example, for the immobilization of enzymes. 27 Xanthan is a bacterial polysaccharide produced by strains of Xanthomonas, a family of plant pathogens. Xanthan consists of a cellulosic backbone with a trisaccharide side chain on every second glucose backbone residue.…”

Effect of chitosan coating on the swelling and controlled release of a poorly water-soluble drug from an amphiphilic and pH-sensitive hydrogel

“…They are of interest not only for industrial applications such as cells encapsulation [1], drug delivery systems [2], separation processes [3] but also for enzymes immobilisation [4]. For biomedical applications, the systems should be biocompatible and stimuli responsive as a function of temperature, pH, etc.…”