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Published on: December 12, 2013
Obtaining biobleached eucalyptus cellulose fibres by using various enzyme combinations
Cristina Valls1, Edith M Cadena, M Blanca Roncero
1Textile and Paper Engineering Department, Universitat Politècnica de Catalunya, Colom 11, E-08222 Terrassa, Spain. cristina.valls@upc.edu
Carbohydrate Polymers
|December 11, 2012
Summary
Enzymatic biobleaching of eucalyptus cellulose fibers using laccase mediators showed distinct lignin and hexenuronic acid removal. Xylanase pretreatment enhanced pulp properties to industrial TCF levels.
Area of Science:
- Biotechnology
- Forest Products Chemistry
- Environmental Science
Background:
- Traditional pulp bleaching methods often involve harsh chemicals with environmental drawbacks.
- Enzymatic bleaching offers a more sustainable alternative for cellulose fiber processing.
- Laccases, in combination with mediators, are explored for their potential in pulp biobleaching.
Purpose of the Study:
- To investigate the efficacy of different laccase-mediator systems for biobleaching eucalyptus cellulose fibers.
- To compare the effects of Trametes villosa laccase with violuric acid (VA(TvL)) and Myceliophthora thermophila laccase with methyl syringate (MeS(MtL)).
- To evaluate the impact of enzyme pretreatment order and combinations with xylanase or cellulase on pulp properties and effluent characteristics.
Main Methods:
- Biobleaching of eucalyptus cellulose fibers using combinations of laccases (TvL, MtL), xylanase, and cellulase.
- Utilizing violuric acid as a mediator for TvL (VA(TvL)) and methyl syringate for MtL (MeS(MtL)).
- Assessing pulp properties, hexenuronic acid content, lignin removal, and chemical oxygen demand (COD) of effluents.
Main Results:
- The VA(TvL) system effectively removed both hexenuronic acids and lignin, while the MeS(MtL) system removed lignin only.
- Applying the mediator before the enzyme improved pulp properties.
- Xylanase pretreatment before the VA(TvL) system yielded pulp properties comparable to industrial TCF sequences; cellulase pretreatment showed no significant effect.
- Enzymatically bleached fibers exhibited reduced hexenuronic acid content.
Conclusions:
- Laccase-mediator systems offer distinct mechanisms for biobleaching, with VA(TvL) being more effective in removing both lignin and hexenuronic acids.
- Optimizing enzyme application order and incorporating xylanase pretreatment can achieve industrially relevant pulp properties.
- Enzymatic biobleaching presents a promising eco-friendly approach for cellulose fiber processing with reduced hexenuronic acid content.
