Purification and properties of an endoglucanase of Aspergillus terreus DSM 826.

Endoglucanase (EG) from A. terreus DSM 826 grown on sugar cane bagasse as a carbon source was purified using acetone fractionation, then a Sepharose-4B chromatographic column, with purification of about 27-fold and 10.5% recovery. The optimum temperature and pH for activity of the purified EG were found to be 50 degrees C and pH 4.8, respectively. The purified enzyme can stand heating up to 50 degrees C for 1 h without apparent loss of activity. However, the enzyme, incubated at 80 degrees C for 5 min, showed about 56% loss of activity. Optimum EG activity was recorded with a citrate buffer system (pH 4.8; 0.05 M). Co2+ (2.5 x 10(-2) M) and Zn2+ (5 x 10(-2) M) were found to activate the purified EG of A. terreus DSM 826 by about 83 and 25%, respectively. On the other hand, Hg2+ inhibited the activity of the purified EG by about 50 and 71% at a concentration of 2.5 x 10(-2) and 5 x 10(-2) M, respectively. Carboxymethyl cellulose was found to be the best substrate for the purified EG, with V(max) values of 4.35 micrpmol min(-1) mg(-1) protein.