Neelam Verma Rajiv Kumar Minhas Sachin Kumar
Present study reports the development of simple, user friendly qualitative cum quantitative biosensor based on urease enzyme for the analysis of urea. Enzyme was isolated from a urease producing microbe originally isolated from National Fertilizer Ltd., Bathinda, which was later found to be a Corynebacterium spp. (MTCC 8143), having log phase between 9-24 hrs. Highest enzyme activity was found to be at 21 hrs. To fabricate biosensor crude enzyme extract and indicator (phenol red) was co-immobilized on nylon membranes with TEOS based hydrosol-gel. Membranes with immobilized biocomponent and indicator when dipped in urea solution, color changed from yellow to red-violet. Time taken for the change in color (response time) was correlated with urea concentration. Urea could be detected in the solution with a detection limit as low as 10-9M with a response time 2 min 29 seconds. Constructed biosensor was applied to human blood and urine samples. Bio-component was stable for 20 days when kept at 40C.
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