Activity And Stability Of Uricase From Lactobacillus Plantarum Immobilized On Natural Zeolite For Uric Acid Biosensor

Determination of uric acid concentration in human urine and blood is needed to diagnose several diseases, especially the occurrence of kidney disease in gout patients. Therefore, it is needed to develop a simple and inexpensive metjod for uric acid detection. The purpose of the research was to observe the use of Indonesian microbe that was immobilized on natural zeolite as a source of uricase fo uric acid biosensor. Selection of mediators and determination ofoptimum condition measurement, the stability and kincetic properties of L. Plantarum uricase wew performed using carbon paste electrode. Cyclic voltammetry was employed to investigate the catalytic behavior of the biosensor. The result indicated that the best mediator for measurement of L. Plantarum uricase activy was Qo (2,3 dimethoxy-5-methyl-1,4 benzoquinone). Optimum conditions for immobilization of 0.015 mM nd zeolite mass at 135 mg Km and Vmas of L. Plantarum uricase obatined from Lineweaver-burk equation for the immobilization uricase directly immobilized into the electrode surface was smaller than Km value of L. Plantarum uricase immobilized on zoelite. The smaller Km value shows the higher afinity toward the substrate. The electrode when kept at 10C was satble until 6 days, however the immobilized electrode on zeolite was stable until 18 days. Therefore, Indonesian L. Plantarum could be used as a uric acid biosensor. Pakistan Journal of Biological Science. Vol. 17 No.2. 2014. P: 277-281