Enzymatic Hydrolysis Of Cellulosic Materials

There are abundant renewable resources in China. In order to make sufficient utilization of them, the method of enzymatic hydrolysis for cellulosic materials was studied.Cellulase production by Trichoderme reesei ATCC 56764 was studied in solid state fermentation. The effects of culture time, temperature, initial pH value and water content of the substrate on cellulase synthesis were discussed. It was found that the FPA (Filter Paper Activity)could reach 158 IU/g dry koji under suitable fermentation conditions, but the CBA(Cellobiase Activity) was low.Cellobiase production by Aspergillus niger LORRE 012 was also studied in solid state fermentation. Under the same fermentation conditions, the CBA could reach 435.6 IU/g dry koji, though there was almost no FPA.Different pretreatment methods, such as dilute acid, NaOH, ammonia steeping and steam explosion, were evaluated for the cellulosic material. The results showed that the pretreatment was important to the properties, morphology and composition of the cellulosic material. After pretreatment, the ability of enzymatic hydrolysis was greatly improved. Among them, dilute acid pretreatment was the most suitable method.The studies of the enzymatic hydrolysis process showed that the hydrolysis efficiency was affected by the dosage of substrate and enzyme. The appropriate concentrations were 100 g/L and 15 FPIU/g respectively.The synergistic action between the cellulase koji produced by Trichoderme reesei and the cellobiase koji by Aspergillus niger wasobvious during the hydrolysis process. When the two kinds of koji were mixed and the ratio of CBA/FPA was increased to 0.42, no cellobiose accumulated in the hydrolysate, and the high hydrolysis efficiency (91.6%) was obtained.After the enzymatic hydrolysis of cellulosic materials, the available reducing sugar could be used in the production of ethanol, SCP, organic acid, etc. It was promising in the comprehensive utilization of the residue and the control of the pollutant.