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Chemical characterization in the biorefinery of lignocellulose: Formation and management of oxalic acid and analysis of feedstocks for bioethanol production
Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

The pulp and paper industry is entering a new era. Pulp mills will be transformed to biorefineries that produce not only pulp, but also biofuels and novel products from lignocellulose. This thesis addresses problems connected with the industrial transition to environmental-friendly technologies and the implementation of the biorefinery concept.

Peroxide bleaching and enhanced recirculation of process water may lead to increased problems with oxalate scaling. Enzymatic elimination of the oxalate problem could be the ultimate industrial solution. The activities of oxalate oxidase, oxalate decarboxylase and a novel oxalate-degrading enzyme provided by Novozymes have been tested in industrial bleaching filtrates. Chemical characterization of the filtrates was used in combination with multivariate data analysis to identify potential enzyme inhibitors. A method based on oxalate oxidase was developed to determine the levels of oxalic acid in process water.

The precursors of oxalic acid formed during bleaching of pulp have been reassessed. New experimental data indicate that alkaline oxidative degradation of dissolved carbohydrates is the main source of oxalic acid. These findings are contradictory to previous hypotheses, which have been focused on lignin. Xylan was more important than lignin as precursor of oxalic acid under peroxide-bleaching conditions. Hot-water extraction of hemicelluloses from softwood mechanical pulp prior to the peroxide-bleaching stage reduced the formation of oxalic acid by one third.

Lignocellulosic materials were characterized chemically with regard to their suitability as feedstocks in biorefineries producing bioethanol. Four agricultural and agro-industrial residues were investigated; cassava stalks, peanut shells, rice hulls, and sugarcane bagasse. Pretreated sugarcane bagasse was the material that was most susceptible to hydrolysis by cellulolytic enzymes. Waste fiber sludges from three pulp mills were characterized. The waste fiber sludge with the lowest content of lignin was hydrolyzed most efficiently by the enzymes. Oligomeric xylan fragments were isolated as by-products from a waste fiber sludge. Hydrolysis of the waste fiber sludges resulted in solid residues with improved fuel properties. The waste fibers were found to be suitable as a feedstock for the production of biofuels in a pulp mill-based biorefinery.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2008. , 56 p.
Series
Karlstad University Studies, ISSN 1403-8099 ; 2008:5
Keyword [en]
biorefinery, enzymes, ethanol, lignocellulosic feedstocks, oxalic acid, scaling
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Research subject
Chemistry
Identifiers
URN: urn:nbn:se:kau:diva-1362ISBN: 978-91-7063-162-7 (print)OAI: oai:DiVA.org:kau-1362DiVA: diva2:5246
Public defence
2008-02-15, Nyqvistsalen, 9C 203, Karlstad, 13:15
Opponent
Supervisors
Available from: 2008-02-01 Created: 2008-02-01 Last updated: 2011-12-21Bibliographically approved
List of papers
1. Xylan is more important than lignin as precursor of oxalic acid during peroxide bleaching of mechanical pulp
Open this publication in new window or tab >>Xylan is more important than lignin as precursor of oxalic acid during peroxide bleaching of mechanical pulp
(English)Manuscript (Other academic)
Identifiers
urn:nbn:se:kau:diva-1965 (URN)
Available from: 2008-02-01 Created: 2008-02-01 Last updated: 2011-12-21Bibliographically approved
2. Enzymatic method for rapid determination of oxalic acid in bleaching filtrates from the pulp and paper Industry
Open this publication in new window or tab >>Enzymatic method for rapid determination of oxalic acid in bleaching filtrates from the pulp and paper Industry
2005 (English)In: Journal of Donghua University, Vol. 22, 64-68 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:kau:diva-1966 (URN)
Available from: 2008-02-01 Created: 2008-02-01 Last updated: 2010-09-07Bibliographically approved
3. Comparison between oxalate decarboxylase and oxalate oxidase in the degradation of oxalic acid in filtrates from the pulp and paper industry
Open this publication in new window or tab >>Comparison between oxalate decarboxylase and oxalate oxidase in the degradation of oxalic acid in filtrates from the pulp and paper industry
Show others...
(English)Manuscript (Other academic)
National Category
Chemical Sciences
Research subject
Chemistry
Identifiers
urn:nbn:se:kau:diva-1967 (URN)
Available from: 2008-02-01 Created: 2008-02-01 Last updated: 2011-11-14Bibliographically approved
4. Enzyme-based control of oxalic acid in the pulp and paper industry
Open this publication in new window or tab >>Enzyme-based control of oxalic acid in the pulp and paper industry
2008 (English)In: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 43, 78-83 p.Article in journal (Refereed) Published
National Category
Biomedical Laboratory Science/Technology Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Research subject
Biomedical Sciences
Identifiers
urn:nbn:se:kau:diva-1968 (URN)10.1016/j.enzmictec.2007.11.014 (DOI)
Available from: 2008-02-01 Created: 2008-02-01 Last updated: 2011-12-21Bibliographically approved
5. Dilute sulfuric acid pretreatment of agricultural and agro-industrial residues for ethanol production
Open this publication in new window or tab >>Dilute sulfuric acid pretreatment of agricultural and agro-industrial residues for ethanol production
Show others...
2007 (English)In: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1599-0291, Vol. 136-140, 339-352 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:kau:diva-1969 (URN)10.1007/s12010-007-9063-1 (DOI)
Available from: 2008-02-01 Created: 2008-02-01 Last updated: 2010-09-07Bibliographically approved
6. The potential in bioethanol production from waste fiber sludges in pulp mill-based biorefineries.
Open this publication in new window or tab >>The potential in bioethanol production from waste fiber sludges in pulp mill-based biorefineries.
2007 (English)In: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1599-0291, Vol. 136-140, 327-338 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:kau:diva-1970 (URN)10.1007/s12010-007-9062-2 (DOI)
Available from: 2008-02-01 Created: 2008-02-01 Last updated: 2010-09-07Bibliographically approved

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