Purification and Characterization of Nattokinase Produced by Local Isolate of Bacillus sp. B24
Abstract
The results presented in this study were based on purifying and characterizing the nattokinase produced from local isolate of Bacillus sp. B24. Nattokinase was purified by two steps including the precipitation by ammonium sulfate at 50% saturation and ion exchange chromatography using DEAE-cellulose. The final purification folds were 16.46 time with an enzyme yield of 30%. The enzyme was stable in temperatures range 25-45°C and pH values of 8.0–9.5, with maximal activity was defined at 60°C and pH value of 8.0, whereas was retained 94% of its activity at 60˚C for 20 min. The presence of KCl, CaCl2, MnCl2, NaCl and MgCl2 was observed to enhance enzyme activity to levels above their original activity, whereas CoCl2, HgCl2 and FeCl3 decreased the enzyme activity. Furthermore, EDTA and PMSF strongly inhibited the enzyme activity suggesting that it is a metalloprotease and serine protease enzyme. The enzyme molecular weight as determined by gel filtration using Sephadex G-150 was found to be 63 kDa. Fibrinolytic activity of the partial purified nattokinase was studied in vitro conditions and it was found that the enzyme has degradation effect.
