Abstract: Urease was immobilized on commercial cotton and commercial cotton activated with glutaraldehyde. The kinetic of urea hydrolysis by free and immobilized urease was studied as a function of pH, temperature and time of hydrolysis. High concentration of ammonia was released at pH 10.0 for free enzyme (0.097 mg/mL) and urease immobilized on cotton (0.092 mg/mL) and pH 4.0 for enzyme, immobilized on activated commercial cotton (0.083 mg/mL). High concentration of ammonia was released at 30 °C for free enzyme (0.006 mg/mL), 25 °C for urease immobilized on cotton (0.043 mg/mL) and urease immobilized on cotton activated with glutaraldehyde (0.015 mg/mL). High concentration of ammonia was released after 10 minutes for free enzyme (0.0016 mg/mL), 60 minutes for inactivated (0.043 mg/mL) and for activated cotton (0.015 mg/ml). The result show that immobilized urease is less effective than the free enzyme and is more active in acid medium than the basic medium.
Keywords: Urease, cotton, immobilization, glutaraldehyde, hydrolysis.