Production of snake melon juice by immobilized enzymes part I: Preparation and enzymic properties of immobilized pectinase and cellulase on glass beads
1994
Kamontip Dumsinin | Pranee Anprung (Chulalongkorn Univ., Bangkok (Thailand). Faculty of Science. Dept. of Food Technolgoy)
Optimum conditions for preparation of immobilized pectinase (IP) and immobilized cellulase (IC) on 2 mm of glass bead by covalent bonding method were found: the reaction condition for IP was with 1 percent by volume of gamma-aminopropyltriethoxysilane (APTS) solution as glass bead activator, 1 percent by volume of glutaraldehyde solution as intermolecular cross-linker and 2 percent by volume of pectinase solution (26,000 Unit/ml) at pH 4.0 while the reaction condition for IC preparation was with 3 percent APTS, 7 percent glutaraldehyde and 6 percent of cellulase solution (1,500 Unit/ml) at pH 4.8. The prepared IP gave optimum pectin hydrolysis at temperature of 50 deg C and pH of 3.6 while the optimum temperature and pH when using free pectinase was at 40 deg C and pH 4.5. In addition, Vmax/Km of the IP was found to be 18.14 (Unit/mg of enzyme protein)/(g of pectin/ml) which was 1.09 times higher than that of the free pectinase, Vmax/Km = 16.65 (Unit/mg of enzyme protein)/(g of pecting/ml). For cellulase hydrolysis, both the IC and free cellulase had an optimum temperature of 60 deg C and the optimum pH of 5.0 for the former and 4.55 for the latter. The Vmax/Km of the IC, Vmax/KM = 69.35 (Unit/mg of enzyme protein)/(g of pectin/ml) of cellulose was 1.93 times of free cellulase, Vmax/Km = 35.92 (Unit/mg of enzyme protein)/(g of cellulose/ml) Furthermore, for repeateds uses for 5 times of the same amount of the IP and the IC in pectin cellulose hydrolysis, it was found that its activity retained 28 percent and 61 percent respectively.
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