Enzymatic modification of pretreated Douglas-fir refiner pulp

Mechanically derived pulp from Douglas fir (Pseudotsuga menziesii) was subjected to a range of chemical pretreatments prior to the application of a xylanase isolated from Thermomyces lanuginosus. Materials solubilized from the fiber wall, as a consequence of chemical treatment, allowed increased permeability during the subsequent enzyme treatment. Positive effects on handsheet strength properties were noted with improvements to interfiber bonding. The combined action of the enzymes and the chemical treatments resulted in decreases in fiber coarseness, thus contributing to improved paper strength.