The current study was designed to isolate and identify cellulose-degrading fungi from Egyptian soils rich in cellulosic compounds, then optimize their cellulose-degrading enzymes production. Among 146 microbial isolates grown on CMC agar medium, 9 isolates were found to be filamentous fungi. Only one isolate was selected as the highest cellulases producer according to the Congo red and cellulase activity assays. This isolate was identified by morphological and genetic characteristics as Aspergillus niger MK543209. After that, to optimize the activities of three cellulose-degrading enzymes (Exo-β-glucanase, Endo-β-1,4-glucanase, β-glucosidase) by this strain, the effect of nutritional and environmental factors was studied. Basal mineral salt medium amended with 1% rice straw was the best medium for cellulose-degrading enzymes production under submerged fermentation (SmF). Additionally, bagasse at 30% and urea at 2% were the best carbon and nitrogen sources, respectively. In respect of the environmental conditions, the optimum temperature, pH and incubation period were 45°C, 5.5 and 7 days, respectively. |
