Purification and Characterization of Phytase from a Local Poultry Isolate of Aspergillus flavus MT899184

The need for exogenous phytase in animal feed processing is increasing due to its ability to breakdown anti-nutrients in grains which constitute a large proportion of animal feeds. This study investigated the production of phytase using indigenously isolated Aspergillus sp. and the characterization of the purified phytase. The Aspergillus sp. was isolated from a poultry site using phytate screening medium (PSM). Quantitative estimation of phytase production was carried out using 2 × 10⁸ spores/100 mL basal medium containing 0.5% sodium phytate as substrate at 30 °C and 150 rpm for 5 days under submerged fermentation condition. The extracted crude enzyme was purified using ammonium sulphate and gel filtration chromatography using Sephadex G-75 gel. The enzyme was characterized by investigating the effect of temperature, pH, and nutrient sources on the purified enzyme. Molecular identification confirmed the isolate as Aspergillus flavus (accession number of MT899184). The total activity observed in crude faction (609 U/mL) reduced to 187.5 U/mL in the ammonium sulphate fraction and then to 77.6 U/mL in the Sephadex G-75 fraction. Optimum temperature and pH were 40 °C and 6, respectively. The enzyme remained active for 5 min at both 70 °C and 80 °C. However, at 100 °C, all activity was lost. Glucose was the preferred carbon source and had higher activity (0.185 U/mL) but was unable to utilize sucrose. This study concludes that this isolate may be exploited for industrial production of phytase which has great application in animal feed industries.