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Development of Coconut Shell Activated Carbon-Tethered Urease for Degradation of Urea in a Packed Bed
journal contribution
posted on 2014-03-03, 00:00 authored by Lei Wang, Sha Wang, Xiangyun Deng, Yucang Zhang, Chunrong XiongCoconut shell activated
carbon (AC)-tethered urease (from jack
bean) was successfully developed to degrade urea in a packed bed reactor.
The loading capacity of urease in AC was 78.8 mg/g. The tethered enzyme
showed a maximum activity at 70 °C and pH 7.2. For higher than
75% of the maximum activity, the tethered urease showed a broader
temperature range of 42–80 °C compared to 45–75
°C for the free enzyme. Similarly, the tethered urease had an
increased stability against the changes of pH. The Km value of the free urease was 0.271 mol/L and 0.345 mol/L
for the tethered one. This may be caused by the conformational changes
of the enzyme. The Vmax values were 0.215
and 0.110 mol/min for the tethered and free ureases, respectively,
which is reflected by an increase in catalytic activity. The catalytic
degradation of urea was performed in a packed bed reactor. The remaining
activity of the tethered urease was over 80% after 50 h of operation.