Study On Biobleaching Bagasse Pulp With Ligninase

The technology and the mechanism of biobleaching bagasse pulp with ligninase secreted from white-rot-fungi were studied in this thesis.At first, white-rot-fungi Phanerochaete Chrysosprium was chosen from three species and its best growth condition were researched. On that condition, the ligninase secreated by Phanerochaete chrysosprium was used to biobleach kraft pulp.The better condition of ligninase treating bagasse pulp is: 45 -55 癈 by temperature, 2-3 hour by time, pH value 4.5-5.0 and dosage of ligniase 2ml/g.The bagasse pulp in the OEnP sequence has higher brightness (71.3%ISO) than the OP pulp (69.1%ISO), and the kappa value and viscosity were reduced slightly compared with the OP pulp. The cooperation of a special lignin-activating agent (X) under acidic condition and alkaline extraction (E) with ligninase treatment was proved to be very effective in improving pulp bleachability.Analysis finds lignin carbohydrate complexes (LCC) from pulp fibers is destroyed after ligninase treatment, thus residual lignin is easy to dissolve and it can improve bleachability of kraft pulps.