LAUSR

The present study is concerned with the screening of microbial strains and suitable fermentation medium for the best production of phytase using solid state fermentation process. The results revealed that fermentation medium M5 gave maximum yield with Aspergillus niger. Different culture conditions such as effect of different carbon and nitrogen sources, different surfactants, their concentration levels, incubation period, incubation temperature, pH of the medium, moisture level and inoculum size on the production of phytase were also studied to improve the yield. The results showed that glucose (1% w/w), NH4NO3 (0.5% w/w) and tween-40 (0.5% w/w) were best carbon source, nitrogen source and surfactant for phytase production, respectively. Maximum activity of enzyme (297.25±7.94 IU/g) was recorded after 5 days of incubation at 35°C, pH 6, with 80% (v/w) moisture level and 10% (v/w) inoculum size, where as the enzyme activity was 198.78±5.80 IU/g under unoptimized cultural conditions. All these results indicate that optimization of culture conditions is very important to improve the production of phytase by Aspergillus niger using solid state fermentation process.