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Studies on Properties of Lipase Produced from Aspergillus sp. Isolated from Compost Soil
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作者 Chijioke O. Ezenwelu Oladejo A. Afeez +3 位作者 Obiano U. Anthony Okoro A. Promise Ude-Ezika C. Mmesoma Oparaji E. Henry 《Advances in Enzyme Research》 CAS 2022年第2期49-60,共12页
Lipase producing Aspergillus was isolated from soil collected from a refuse dump site located at Awka, Anambra State, Nigeria using standard microbiology and biochemical techniques. Crude extract of lipase was produce... Lipase producing Aspergillus was isolated from soil collected from a refuse dump site located at Awka, Anambra State, Nigeria using standard microbiology and biochemical techniques. Crude extract of lipase was produced after a successful screening of the isolates using mineral broth containing p-NPP through submerged fermentation system with optimized physiologic conditions. Three steps of purification were carried out: Ammonium sulphate, dialysis and gel filtration (sephadex G-150). Crude extract was precipitated by using 70% saturation of ammonium sulphate at pH 6.0 which gave the optimum precipitation of the protein with specific activity of 260.56 U/mg. Precipitation using ammonium sulphate carried out at pH 6.5 and 8.0 gave specific activity of 217 U/mg of the protein. The precipitates were further desalted through dialysis for twelve hours and specific activity of 343.20 U/mg was recorded from the dialysate afterwards. Further purification was done by using sephadex G-150 and specific activity of 490.55 U/mg was recorded from the active pooled fractions. The purification table showed a 2.32 purification folds of lipase was gotten after gel filtration (sephadex G-150) with a lipase percentage yield of 2.00%. The specific activity of lipase increased from 211.81 to 490.55 U/mg. Characterization of β-galactosidase gave optima pH and temperature of the enzyme at 6.0 and 60°C respectively. Kinetic constants: K<sub>m</sub> and V<sub>max</sub> values were obtained at various concentrations of p-NPP where 0.32 mM and V<sub>max</sub> of 200.00 μmol/min respectively. Ca<sup>2+</sup> and Co<sup>2+</sup> showed greater effect on lipase activity in a concentration-dependent manner (0.03 - 0.05 M) when compared to Mn<sup>2+</sup> and Fe<sup>2+</sup>. The results from this study have shown that lipase produced from filamentous Aspergillus has a wide range of activity over physiologic conditions in regards to industrial and clinical standard operational procedures. 展开更多
关键词 LIPASE purification Specific Activity Precipitation purification folds
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