Study of Enzymatic Prebleaching Effect on Optical Properties of Bagasse Kraft Pulp in ECF Bleaching

The effect of commercial xylanase enzyme in prebleaching of bagasse kraft pulp was investigated. Xylanase enzyme from Trichoderma viride was added to pulp at various doses of 5, 10, 25 and 50 IU/g pulp for reaction time 2h and then the enzyme treated pulp was bleached in D1ED2 sequences (using Dioxide chlorine 4, 6, 8, 10% + Alkaline extraction + Dioxide chlorine 2% as active chlorine). The results showed that enzymatic treatment improved brightness and opacity and decreased yellowness, kappa number and revolution of refiner for given freeness of bleached pulp significantly (P<0.01). Maximum of brightness and opacity and minimum of kappa number were related to 25IU/g pulp treatment, which had about 13.1%, 1.46% and 2.23 unit significant difference in comparison with those of the control sample, respectively. Minimum of yellowness was related to 50IU/g pulp treatment which had about 7.32% significant difference as compared with control sample. Regard to the obtained results, the 25IU/g pulp treatment could be suggested as optimum treatment.