The crude jackbean preparation was used as urease to determine the Km((app)), V-(app), and substrate conversion (%) at different flow rates in a hollow fiber device. It was found that, as the flow rate increases, the V-(app) increases, whereas the Km((app)) initially decreases and again increases. The maximum substrate conversion (96.25%) was obtained at the lowest Km((app)). No significant loss was observed in substrate conversion after 2 mo at room temperature.