Enhanced Phytase Production from Indigenous Bacillus subtilis KT004404 by Response Surface Methodology to be Used as Poultry Feed Supplement

composite design (CCD), Response surface methodology (RSM)The aim of this experimental study was the optimization of phytase production from Bacillus subtilis KT004404 through statistical model (Response Surface Methodology) by utilizing centrally composite design (CCD).The optimal phytase activity obtained after CCD design was 132.32 U/mL at 35 °C, pH 6.5, inoculum density of 2.5mL after incubating for 24h at 75 rpm.Extracellular enzymes were then partially purified in 2 steps (ammonium sulfate precipitation and gel filtration chromatography using Sephadex G-50).The molecular weight of extracellular phytase from B. subtilis KT004404 estimated by SDS-PAGE was 30 kDa.The K m and V max of B. subtilis KT004404 phytase were 0.175 mM and 250 U/mL (phytase activity) respectively.The optimum temperature for partially purified extracellular phytase was 40°C, and the optimum pH range for extracellular phytase activity was pH 6.5-7.0.The extracellular enzyme activity was not significantly affected by Cu 2+ and Mn 2+ metal ions while the inhibitory effect of Ca 2+ , Co 2+ , Zn 2+ , Hg 2+ and Fe 2+ was recorded with 27.12%, 32%, 57.31%, 14.76% and 13.54% residual activity.