| Abstract: | A method of enzyme immobilization by graft-copolymerization onto polysaccharides is reported. Bisacryloylpiperazine has been used as a vinylating reagent and the reaction product with several enzymes (HRP, GOD, Am, ChT, Cel) was copolymerized onto different matrices (cellulose, Sepharose, Sephadex, starch). Immobilization parameters which influence the copolymer activity have been studied for the insolubilization of horseradish peroxidase onto cellulose. These parameters are pH, time, and temperature of bisacryloylpiperazine enzyme activation reaction. Under the best immobilization conditions copolymer activity linearly depends on enzyme concentration. Enzyme coupling efficiency depends on the type of enzyme and it ranges from 7 to 20%. The most important characteristics of these immobilized enzyme systems were tested and compared with those of similar systems obtained by glycidylmethacrylate enzyme activation (stability in continuous washing, kinetic characteristics, and storage, thermal, and operational stability). Immobilized enzyme graft copolymers have kinetic behaviour very close to that of the free enzymes. Diffusion is not seriously limited because immobilization reaction does not alter the enzymatic activity. By means of bisacryloylpiperazine it was possible to immobilize chymotrypsin with better results than those previously obtained, particularly coupling efficiency and long term continuous working. |
