Abstract
In the present work purification and characterization of cellulase was studied which was produced from Aspergillus fumigatus (Fresenius, 1863) when it was grown in 50 mL of culture medium containing sunflower waste powder as substrate after 120 h, temperature 30° C, at initial pH 5.0, agitation rate 50 rpm and inoculum size 6x106 conidia. Celluase was purified first by ammonium sulfate precipitation and then Bio-Gel P-100 chromatography to about 9.8 folds than crude enzyme with the recovery of 58.6 % having specific activity 268.2 U/mg. Kinetic constants (Km 3.32 mM and Vmax 188.7 U/mL/min) were determined by Lineweaver-Burk Plot and molecular mass (33 kDa) by 12 % SDS-PAGE. Cellulase showed maximum activity at pH 6.0 (121.7 U/mL) and at the temperature of 55° C (106.8 U/mL). The purified cellulase was activated by MnCl2 (139.6 U/mL) and CoCl2 (148.4 U/mL) but inhibited by HgCl2 (21.6 U/mL), CdCl2 (32.7 U/mL), FeSO4 (29.5 U/mL) and Fe2 (SO4 )3 (49.5 U/mL The value of Km of the purified cellulase shows that its natural substrate is carboxymethyl cellulose and therefore it is considered to be endocellulase which is highly benefits to the industrial application.
