How to Cite: Moradpour , Z., Daryani , M. E., Diba, K., & Ghasemian , A. Medium optimization for extracellular urate oxidase production by a newly isolated Aspergillus Niger. International Journal of Health Sciences, 47962–47975. Retrieved from https://sciencescholar.us/journal/index.php/ijhs/article/view/13408 International Journal of Health Sciences ISSN 2550-6978 E-ISSN 2550-696X © 2022. Manuscript submitted: 9 May 2022, Manuscript revised: 18 July 2022, Accepted for publication: 27 August 2022 47962 Medium optimization for extracellular urate oxidase production by a newly isolated Aspergillus Niger Zahra Moradpour Research Center for Experimental and Applied Pharmaceutical Sciences, Urmia University of Medical Sciences, Urmia, Iran and Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran Mahya Effati Daryani Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran Kambiz Diba Department of Parasitology, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran Abdollah Ghasemian * Research Center for Experimental and Applied Pharmaceutical Sciences, Urmia University of Medical Sciences, Urmia, Iran, Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran P.O. Box 57157-1441, Urmia, Iran. Tel.:+98-44-32754991, Fax: +98- 44-32754990; ORCID: https://orcid.org/0000-0001-7743-1085 *Corresponding author email: abdollahghasemian@umsu.ac.ir Abstract---Urate oxidase is a peroxisomal enzyme with four equal subunits that convert uric acid to allantoin, a more soluble metabolite for excretion. The usage of uricase as a drug in medicine is to treat hyperuricemia. Many microorganisms have been used for uricase production such as Streptomyces exfoliates, Pseudomonas aeruginosa, and Aspergillus flavus. In this study, soil samples were collected and then cultured in a screening medium including uric acid as the sole carbon source. Samples with the higher ability of uricase production were selected for enzyme assay. Enzyme activity was measured by spectrophotometry and the sample with the maximal uricase activity was identified as Aspergillus niger and selected for further studies. According to the results of experiments, the optimized temperature for enzyme production by Aspergillus niger was determined to be 35±2°C.