A Study on the Potential of Uricase Production by Halophilic Bacteria and Enzyme Production Optimization

Uricase (EC 1.7.3.3) was first utilized in the 1970s, to prevent the uric acid increase in the blood stream and the formation of urate crystals. Later, this enzyme was produced using recombinant DNA technology. However, immunogenic responses towards the alien protein in some patients has led to searching for new uricases with more desirable properties. Considering the interesting characteristics of enzymes of halophilic and halotolerant bacteria, the potential of 85 native Iranian halophilic bacteria isolated from Urmia salt lake for uricase production was evaluated, and the best producer was identified by means of 16S rRNA gene sequencing with more than 99% similarity to Halomonas sulfidaeris. In the following, significant physicochemical and environmental factors for optimal production of uricase by the selected strain were determined. The best combination of effective factors for the enzyme production was identified by Response Surface Methodology (RSM). The optimum enzyme production was found to be at pH=8, 34.5°C, 3% NaCl, and 7.5g/L of uric acid which resulted in the significant production of 32.5U/ml. This strain can be used in subsequent studies regarding the therapeutic application of this halotolerant enzyme.