Jornal de Proteômica e Enzimologia

Partial Purification and Characterization of Cellulase (Ec.3.2.1.4) from Aspergillus niger Using Saw Dust as Carbon Source

Ekpa Emmanuel* and Adebisi Queen

Cellulase (EC.3.2.1.4) was isolated and partially purified from the submerged culture of Aspergillus niger through a simple four step purification step using homogenization to obtain crude filtrate, ammonium sulphate precipitation, carboxymethyl cellulose chromatography, and sephadex G-200 chromatography. A purification fold of 1.00 and 1.26 were gotten for crude filtrate and ammonium sulphate precipitation respectively, while 0.56 and 0.41 were gotten for carboxymethyl cellulose and sephadex G-200. The highest yield of 96.4% was recorded for (NH4)₂SO₄ precipitation. Kinetic studies gave Km and Vmax of 0.01 mg/ml and 1.02 μmole/ml/min for carboxymethyl cellulose and 0.02 mg/ml and 0.96 μmole/ml/min for sephadex G-200. Optimum temperature and pH of 40°C and 8.0 were obtained for the cellulase. Ethanol was found to inhibit the activity of the enzyme higher than other inhibitors tested. The implication of this is that given a more suitable carbon source and a longer culturing time, a very useful cellulase with commercial value could be produced.