THE PROPERTIES OF IMMOBILIZED INVERTASE ONTO A NEW SUPPORT MATERIAL; POLY(METHACRYLAMIDE/MALEIC ACID) COPOLYMERIC HYDROGEL

Poly (methacrylamide / maleic acid) PM/MA and poly (methacrylamide) PM hydrogels were prepared aiming to be used as a support for invertase. Spectrophotometric, thermal analysis methods, swelling and diffusion experiments were used for the characterization of hydrogels. The swelling of PM/MA was higher than that of PM in water. The diffusion of water within the hydrogel was found to be non-Fickian. Invertase was immobilized onto PM and PM/MA (samples named PM-I and PM/MA-I respectively). The optimum pH values were found to be; 6.0, 5.0 and 5.5 for free invertase, PM-I and PM/MA-I respectively. The optimum temperature values were found to be 30 degrees C, 35 degrees C and 40 degrees C for free invertase, PM-I and PM/MA-I respectively. The Michaelis constant (K-m) and maximum velocity of the enzymes (V-max) were K-m: 11,75 mM, V-max: 1,95 mu mol min(-1) for free invertase, K-m: 67,24 mM, V-max: 60,6 mu mol min(-1) for PM-I and K-m: 74,55 mM, V-max: 18,12 mu mol min(-1) for PM/MA-I. PM/MA-I showed excellent thermal, operational and storage stability.