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Biological bleaching of chemical pulps.
- Source :
-
Critical reviews in biotechnology [Crit Rev Biotechnol] 2004; Vol. 24 (1), pp. 1-58. - Publication Year :
- 2004
-
Abstract
- Use of biotechnology in pulp bleaching has attracted considerable attention and achieved interesting results in recent years. Enzymes of the hemicellulolytic type, particularly xylan-attacking enzymes, xylanases are now used commercially in the mills for pulp treatment and subsequent incorporation into bleach sequences. The aims of the enzymatic treatment depend on the actual mill conditions and may be related to environmental demands, reduction of chemical costs or maintenance or even improvement of product quality. The use of oxidative enzymes from white-rot fungi, that can directly attack lignin, is a second-generation approach, which could produce larger chemical savings than xylanase but has not yet been developed to the full scale. It is being studied in several laboratories in Canada, Japan, the U.S.A. and Europe. Certain white-rot fungi can delignify kraft pulps increasing their brightness and their responsiveness to brightening with chemicals. The fungal treatments are too slow but the enzyme manganese peroxidase and laccase can also delignify pulps and enzymatic processes are likely to be easier to optimize and apply than the fungal treatments. Development work on laccase and manganese peroxidase continues. This article presents an overview of developments in the application of hemicellulase enzymes, lignin-oxidizing enzymes and white-rot fungi in bleaching of chemical pulps. The basic enzymology involved and the present knowledge of the mechanisms of the action of enzymes as well as the practical results and advantages obtained on the laboratory and industrial scale are discussed.
- Subjects :
- Biodegradation, Environmental
Endo-1,4-beta Xylanases metabolism
Glycoside Hydrolases metabolism
Industrial Waste prevention & control
Lignin isolation & purification
Lignin metabolism
Water Purification methods
Basidiomycota enzymology
Color
Endo-1,4-beta Xylanases chemistry
Glycoside Hydrolases chemistry
Lignin chemistry
Paper
Wood
Subjects
Details
- Language :
- English
- ISSN :
- 0738-8551
- Volume :
- 24
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Critical reviews in biotechnology
- Publication Type :
- Academic Journal
- Accession number :
- 15328766
- Full Text :
- https://doi.org/10.1080/07388550490465817