Adsorption of hemicellulases onto bleached kraft fibers

The presence of a cellulose binding domain was the main factor which influenced the adsorption of two Trichoderma reesei mannanases and a Trichoderma longibrachiatum xylanase onto bleached kraft fibers. The mannanase containing the binding domain adsorbed to a much greater extent than the mannanase and xylanase without binding domains. Once-dried fibers exhibited lower hemicellulase adsorption than the never-dried fibers. The adsorption onto once-dried fibers was only 30–50% the amount adsorbed onto virgin fibers. Adjustment of the ionic strength and pH of treatment was used to modify the charge on the fibers. Ionic strength had opposite effects on mannanase and mannanase core adsorption. Mannanase adsorption increased at high ionic strengths, while the mannanase core adsorption decreased. An increase in pH and fiber charge significantly enhanced the adsorption of xylanase.