Potential of laccases in softwood-hardwood high-yield pulping and bleaching

The development and use of biotechnology in the pulp and paper industry started in the early 1970s and depends mainly on the production of inexpensive biocatalysts in enormous volumes and weights for industrial applications. Some biotechnical processes have already been implemented in the industry, such as bio-bleaching with xylanases, pitch reduction with lipases, and enzymatic deinking. This chapter discusses the potential of laccases in softwood–hardwood high-yield pulping and bleaching. It is suggested that laccase is an interesting alternative to enhance thermomechanical pulp quality and boosting peroxide bleaching. Depending on the enzymatic treatment conditions and the fungus used to produce them, the results are more or less interesting. Some energy savings could be envisaged with laccase treatment of wood chips. Introducing a pre-bleaching stage with laccase without mediator in the oxidizing bleaching sequence could reduce production costs: about 15 % of the peroxide could be saved to reach the same level of brightness in a shorter time than by the conventional bleaching. Some additional experiments are needed to verify some results, to optimize the different treatments, and to understand what are the involved mechanisms and reactions.