Optimization and production of uricase enzyme from Aspergillus niger isolated from Mangrove sediment

The present study was on isolation of a potent fungal strain from mangrove sediment for the optimization and production of uricase enzyme. Among the 6 fungal strains isolated, Aspergillus niger was found to be a potent uricase producer and it was further used for the optimization studies for uricase production. The optimum cultural parameters that were found to be ideal for the higher uricase production by A. niger were incubation time – 96hrs, agitation speed – 150 rpm, pH 8, temperature – 30C, salinity – 2%, sucrose – 10% (w/v), uric acid 0.4% (w/v). The observed maximum biomass and uricase enzyme activity for the ideal parameters were as given in brackets at pH-8 (6.2g/L and 143 U/ml/min), 30C (5.8 g/L and 140 U/ml/min), 2% NaCl (6.3g/L and 140U/ml/min), sucrose as a carbon source (6.1g/l and 144U/ml/min), 10% sucrose (6g/L and 141 U/ml/min), uric acid as nitrogen source (6.4g/L and 140 U/ml/min) and 0.4% uric acid (5.9g/L and uricase activity of 140 U/ml/min) were observed respectively. In the present study the maximum biomass and uricase production observed in shake flasks with standard substrate i.e. (10% sucrose and 0.4% uric acid) was 7.18g/L and 162U/ml/min. When poultry waste as a cheaper substrate in mass scale production in shake flask, the biomass and uricase activity observed were respectively 6.7g/L and 135U/ml/min. Similarly in fermentor the biomass and enzyme production using standard and cheaper substrates were 9.6g/L and 232U/ml/min. and 8.4g/L and 189U/ml/min. respectively.