Influence of lipase in swelling behavior of hydrogel, morphological properties of hydrogels and enzymatic polymerization reaction of PCL by using lipase immobilized hydrogels

Lipase immobilized superabsorbent hydogels were prepared by crosslinking chitosan with glutaraldehyde. In order to increase the water holding capacity of chitosan hydrogels, they were modified using lipase enzyme in different loading degrees and the optimum amount of enyzmes was determined. The swelling behaviours of chitosan hydrogel and lipase immobilized superabsorbent hydrogel were investigated by gravimetric measurements with different pH values and at different intervals of time. Lipase immobilized superabsorbent hydrogels were fully characterized with FT-IR, TGA, DSC, XRD and SEM analyses. The study aims at presenting the use and development of original catalytic systems based on lipases which are efficient for polyester synthesis and allowing the preparation of biomaterials based on chitosan hydrogels. For this, ε-caprolactone (ε-CL) polymerization catalyzed by immobilized Candida antarctica lipase B (CALB) onto superabsorbent hydrogel was carried out in the presence of gluteraldehyde to obtain biomaterials through polymer chains grafting and growth from the hydroxyl groups of the chitosan. Immobilized form of CALB onto superabsorbent hydrogel has been tested as catalytic systems and its efficiency has been discussed.