ABSTRACT
This review covers the application of microorganisms and the enzymes that they produce in the manufacturing of chemical and mechanical pulp. Biopulping research, mainly aimed at mechanical pulping, has focussed on application of fungi as a pretreatment prior to rening. Biobleaching, on the other hand, usually employs microbial enzymes, especially in production of bleached kraft pulp. Although the primary target of biopulping and biobleaching is lignin modication or removal, in fact other effects are also evident, such as increased cell wall porosity in biopulping, and hemicellulose hydrolysis in biobleaching. Thus the review covers mechanistic aspects of both lignin modication and other cell wall changes associated with biological pulping and bleaching. Currently biopulping with fungal cultures and biobleaching with laccase and mediators have only been demonstrated at a pilot scale, while biobleaching with xylanase is in use in several kraft mills.
