Uricase Activity of Halophilic Bacteria from Iranian Salt Lakes

Higher plants and microorganisms produce uricase that oxidizes uric acid to allantoin. The lack of uricase in higher primates and humans causes uric acid accumulation. Today, the uricase treatment of hyperuricemia has been considered as a remedy. Uricases vary slightly in their origins and structures. Halophilic bacteria synthesize uricase with acidic amino acids at the surface. Fifty-eight halophilic strains isolated from Iranian saline lakes were screened for uricase production. The bacteria were cultured on a medium containing 5% salt and 0.3% uric acid and were assayed at 293 nm. The cultures were optimized by analyzing the effect of physical and chemical factors on the bacterial biomass and uricase production. Out of 18 strains, those were positive for uric-lytic activity, Halobacillus sp. strain GCFx14 with the highest uricase activity at (0.131 U/ml) showed the closest relationship to Halobacillus trueperi (99.00%), and Halobacillus profundi and Halobacillus faecis (98.87%), respectively. The optimum temperature for uricase activity (0.261 U/ml) was 40 degrees C. The mass of Halobacillus sp. strain GCFx14 produced uricase with the activity of 0.233 U/ml at pH 9, while 1% salinity led to 0.215 U/ml activity of uricase. pH of 8.0, temperature of 35 degrees C, salinity of 2.5%, and 0.2% uric acid were the optimum conditions to produce the highest amount of uricase in Halobacillus sp. strain GCFx14. The highest induction of uricase production in the strain was obtained using yeast extract and peptone (meat) as nitrogen and carbon sources.