Deinking of recycled mixed office paper using two endo-glucanases, CelB and CelE, from the anaerobic fungus Orpinomyces PC-2

Optimization studies of hydrogen peroxide bleaching were carried out on two kinds of kenaf mechanical pulps. One was composed of whole kenaf with 65% core fiber (kenaf), and the other was made and 64.0%, respectively, with only 1.0% H 2 O 2 and 1.0% NaOH. With higher H 2 O 2 and NaOH dosages, both pulps can be bleached to 75.0% ISO brightness. Results showed that peroxide consumption is higher for whole kenaf than for bark-22, probably because core fibers are higher in extractives and lignin. For each combination of H 2 O 2 and NaOH dosages tested, the bleaching efficiency was better for bark-22 than for kenaf. Application: Kenaf bark pulp may be a suitable raw material for newsprint and specialty papers in countries where wood resources for fiber are in short supply.