Vol. 1, Issue 6 (2014)
Optimal conditions for Aspergilus fumigatus to biosynthesize endo-ÃŸ-1,4-glucanase and its physico-chemical characteristics
Author(s): Nguyen Phuoc Minh
Abstract: Cellulases are a group of hydrolytic enzymes capable of degrading cellulose to smaller sugar components like glucose units. These enzymes are produced by fungi and bacteria. The aim of this research was to identify a Aspergillus fumigatus with over production of endo-Î²-1,4-glucanase. Properties of endo-Î²-1,4-glucanase from a culture filtrate of the Aspergillus fumigatus was also studied. Our results show that Aspergillus fumigatus can biosythesized endoglucanase utmost after 96 hours of cultivation in MT1 medium, pH 6.5, shaking 200 rpm at 30o C, substrate CMC 2%, carbon source from soybean waste (3%) and ammonium acetate (0.3%). This endoglucanase enzyme presents some major properties: optimal reaction at temperature 50 oC, pH 5.0; stability at 30-50 oC, pH 4.5-5.5. At 5, 10 and 15 mM endoglucanase activity is increased by Fe2+, Cu2+ and EDTA. Meanwhile Ag+, K+, Mn2+, Ni2+, Zn2+, Ca2+, CO2+ can decreased endoglucanase activity; especially Ag+ can decreased endoglucanase dramatically to 43% at concentratio 15 mM after 2 hours of incubation at 37oC. Several solvents such as acetone, ethanol, methanol, iso propanol and n-butanol are able to reduce endoglucanase activity.Â Partically, 30% methanol decreases endoglucanase activity to 52% after 2 hours of incubation at 37 oC. Detergents are demonstrated in lowering endoglucanase activity; especially SDS can reduce this enzyme activity to 20% after incubation with 2% SDS in 2 hours at 37 oC.