Effect of the Enzyme Lipase on Delignification of Kraft Pulp

The influence of enzyme dose in the unwhitened kraft pulp delignification sequence, treatment with Lipex 200L lipase enzyme and bleaching by hydrogen peroxide, was studied. The Kappa number could be reduced by 4-5 units if a small amount of enzyme was used. A negative effect expressed as an increase of the Kappa number to the initial values was observed if the enzyme dose was increased. IR spectroscopy showed that the enzyme increased water adsorbed on the fibers by 1.2-1.7 times for broadleaf and conifer pulp regardless of its percent content.