Purification and Some Properties of Cellulases from Aspergillus niger

Four types of cellulases, FI-1-b, FI-2-b, FI-2-c, and FII, were obtained from a commercial crude cellulase preparation produced from a water extract of a culture of A. niger. Ammonium sulfate fractionation and column chromatography using DEAE-Sephadex A-25, Amberlite IRC-50 and Hydroxylapatite were employed for the purification of these cellulases. Some properties of these enzymes were investigated: the optimum pH for the hydrolysis of glycol cellulose by FI-2-b and FI-2-c was pH 4.0 to 5.0, while that of FI-1-b was pH 2.3 to 2.5, and the optimum temperature for the activity of FI-2-b and FI-2-c was 40°C, but that of FI-1-b was 65°C. The FII seemed to be most active toward cellobiose. Studies of the mode of action on glycol cellulose indicated that A. niger cellulases seemed not to be capable of attacking highly polymerized cellulose.