Synergistic Hydrolysis of Cellulose in Paper Sludge Using Mixed Enzyme System

초록

Paper sludges, generated as a waste in paper industries, contains about 30% of fine cellulose, which can be converted to valuable substances, such as ethanol and organic acids. Cellulases, being produced by fungi, such as Trichoderma reesei, consist of endo- and exo-glucanase, which hydrolyzes the amorphous and crystalline portion of cellulose, respectively, to produce cellooligosaccharides and cellobiose. Cellobiose, in turn, is hydrolyzed by b-glucosidase, being produced by Aspergillus niger, to glucose. These two enzymes, cellulase and b-glucosidase, are known to have a synergistic effect in the hydrolysis of cellulose to glucose. In this study, an appropriate mixed enzyme system was designed experimentally for the hydrolysis of cellulose in paper sludges. The optimum concentration of cellulase which was measured as the content of endo-glucanase was 10 U/ml, while that of b-glucosidase was 8 U/ml. The degree of hydrolysis shown as the amount of glucose produced were 15, 27 and 35 g/L for the solution with the sludge concentration of 5, 10 and 15%, respectively. Based upon this experimental result of enzymatic cellulose hydrolysis, a process of organic acid production from paper waste is being developed.