Enzyme action of the laccase-mediator system in the pulp delignification process

The present work aims a systematic kinetic investigation of the delignification action of the laccase-mediator system in the presence of oxygen. A dimensionless quantity alpha representing the degree of delignification was used as a criterion for the enzyme efficiency. It was found that the exponential equation which describes the kinetics of processes taking place on a uniformly inhomogeneous surface, fits the experimental results with the highest degree of statistical confidence. The activation energy E obtained is independent of the delignification degree alpha while the pre-exponential factor A decreases in the course of the process. It is mostly connected to spatial limitations, the exhaustion of phenolic subunits available as well as to the decrease of the indirect activity of the non-phenolic structure in the lignin.