Purification and properties of an endoglucanase of Aspergillus terreus DSM 826

Abstract

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.

Optimization and characterization of cold-active endoglucanase produced by Aspergillus terreus strain AKM-F3 grown on sugarcane bagasse

“…The present K m value is lower than that obtained for EGs from A. terreus GN1 (13.1 mg/mL) (Garg and Neelakantan, 1982). From the present study, the V max from A. terreus strain AKM-F3 was higher than the V max obtained from A. niger VTCC-F021 (20.121 U/mg protein) (Pham et al, 2012) and A. terreus DSM 826 (4.35 U/mg protein) when CMC was used as a substrate (Elshafei et al, 2009). …”

“…The CAEG from A. terreus strain AKM-F3 showed high activity in an acidic pH but it also showed relative activity above 70% at pH 8.0-9.0. A. terreus DSM 826 showed almost the same result with an optimum EG activity at pH 4.8-5.0 (Elshafei et al, 2009). The optimum pH for the stability of EG from A. terreus strain AKM-F3 was found to be pH 7.0 (100% relative EG activity = 26.17 U/mg) and almost 90% of relative activity was shown at pH 5.0-8.0 ( Figure 13).…”

Industrial Applications of Endoglucanase Obtained from Novel and Native Trichoderma atroviride

“…It is proposed that fungiobtained endoglucanase has mesophilic properties. 5 While the cellulases from A. terreus DSM 826 and A. glaucus XC9 have optimum temperature (50 °C) similar to our enzyme 3,5 , the EG from T. atroviride 676 has higher optimum temperature. 20 Tao et al had indicated that T. reesei, the most popular industrial cellulase producer, has optimum temperature at 52 °C.…”

“…5b). Because the EG from T. atroviride showed optimum activity at pH 5.0, it can be said that the obtained enzyme has acidic properties according to Araǔjo et al 31 The optimum pH of this enzyme obtained from T. atroviride was same as that from A. aculeatus 32 and differed slightly from T. atroviride 676 (pH 4.0), 20 T. reesei QM-9414 (pH 4.5), 33 A. terreus DSM 826 (pH 4.8) 3 , and A. glaucus XC9 (pH 4.0). 5 Usage of acidic cellulases is more suitable for degradation of lignocellulosic materials, and biostoning and finishing of cellulosic fibers in the textile industry.…”

“…2 For effective degradation of cellulose, a complete enzyme system is necessary, which comprises three classes of enzymes; endo-β-1,4-glucanase (CMCase, EC 3.2.1.4, EG; randomly cleaving β-linked bonds within the cellulose molecule), cellobiohydrolases (EC 3.2.1.91, CBH; removing cellobiose units from nonreducing ends of the cellulose chain) and β-glucosidase (cellobiase, EC 3.2.1.21, hydrolyzing cellobiose and cellooligosaccharides to glucose). 3,4,5 These cellulases can be produced by most microorganism, including fungi, bacteria, and actinomycetes. Trichoderma and Aspergillus species are the most studied cellulolytic microorganisms for cellulase production.…”