Natural papermaking raw materials include grass, wood, hemp, cotton and so on. These raw materials are mainly composed of three parts: cellulose, hemicellulose and lignin. The cooking process of paper mill is the process of dissolving and removing lignin with chemicals. In general, chemical pulping not only uses various chemicals, but also costs a lot and consumes a lot of energy. Bio-enzymatic degradation of lignin is simple and environmentally friendly. The main enzymes used in paper industry
are laccase and ligninase. Laccase is a kind of extracellular oxidase containing copper. Laccase can make lignin biodegradable. Lignin degrading enzymes
can be divided into lignin peroxidase and manganese peroxidase, which can catalyze the degradation of lignin.
Biopulping is the process of further separating lignin biodegradable raw materials from lignin biodegradable raw materials by combining chemical, mechanical pulping and other biological enzymes
. Different enzymes
are used in different materials. If phloem fibers have pectin, pectinase can be used to decompose pectin and release cellulose. Pectinases used to decompose pectin are mainly pectin depolymerase and pectin esterase. Both straw pulp and wood pulp contain more lignin, which can be pulped by combining lignin degrading enzymes
with chemical pulping and mechanical pulping. Bio-sulfate pulping and bio-sulfite pulping are the methods of biological treatment of papermaking raw materials before sulfate pulping and sulfite pulping. They are the combination of biological method and traditional sulfate pulping and sulfite pulping. The biomechanical pulping is same.
Biobleaching of pulp is a process of improving pulp whiteness by utilizing microorganisms or enzymes
produced by them to interact with some components of pulp. There are two main enzymes
for pulp biobleaching: hemicellulase and lignin degrading enzymes
. Hemicellulase includes xylanase and mannanase; lignin degrading enzymes
mainly include lignin peroxidase, manganese peroxidase and laccase. There are also direct bleaching pulps with white rot fungi. The main purpose of biobleaching is to improve pulp performance and reduce bleaching pollution without or with less chemical bleaching agents.