Utilization of Urease for Decomposition of Urea in Sake

For decomposition of urea in sake, urease having activity at acidic side was studied.The optimum pH of the urease was 4.5-5.5, and it lost the activity perfectly by heating at 75°C for 15 min.Amounts of urea decomposed were proportional to temperature till 25°C, and also enzyme concentration and urea concentration.In order to obtain over 90% of urea decomposition rate in sake, it took 14 days at 10°C, and 3 days at 20°C by using enzyme concentration of 5 U/g.