Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Enzyme-based control of oxalic acid in the pulp and paper industry
Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
STFI-Packforsk AB, Swedish Pulp and Paper Research Institute, Stockholm.
Karlstads universitet, Fakulteten för teknik- och naturvetenskap, Avdelningen för kemi och biomedicinsk vetenskap.
2008 (Engelska)Ingår i: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 43, s. 78-83Artikel i tidskrift (Refereegranskat) Published
Ort, förlag, år, upplaga, sidor
2008. Vol. 43, s. 78-83
Nationell ämneskategori
Biomedicinsk laboratorievetenskap/teknologi Medicinsk bioteknologi (med inriktning mot cellbiologi (inklusive stamcellsbiologi), molekylärbiologi, mikrobiologi, biokemi eller biofarmaci)
Forskningsämne
Biomedicinsk vetenskap
Identifikatorer
URN: urn:nbn:se:kau:diva-1968DOI: 10.1016/j.enzmictec.2007.11.014OAI: oai:DiVA.org:kau-1968DiVA, id: diva2:5243
Tillgänglig från: 2008-02-01 Skapad: 2008-02-01 Senast uppdaterad: 2017-12-07Bibliografiskt granskad
Ingår i avhandling
1. Chemical characterization in the biorefinery of lignocellulose: Formation and management of oxalic acid and analysis of feedstocks for bioethanol production
Öppna denna publikation i ny flik eller fönster >>Chemical characterization in the biorefinery of lignocellulose: Formation and management of oxalic acid and analysis of feedstocks for bioethanol production
2008 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
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.

Ort, förlag, år, upplaga, sidor
Karlstad: Karlstads universitet, 2008. s. 56
Serie
Karlstad University Studies, ISSN 1403-8099 ; 2008:5
Nyckelord
biorefinery, enzymes, ethanol, lignocellulosic feedstocks, oxalic acid, scaling
Nationell ämneskategori
Medicinsk bioteknologi (med inriktning mot cellbiologi (inklusive stamcellsbiologi), molekylärbiologi, mikrobiologi, biokemi eller biofarmaci)
Forskningsämne
Kemi
Identifikatorer
urn:nbn:se:kau:diva-1362 (URN)978-91-7063-162-7 (ISBN)
Disputation
2008-02-15, Nyqvistsalen, 9C 203, Karlstad, 13:15
Opponent
Handledare
Tillgänglig från: 2008-02-01 Skapad: 2008-02-01 Senast uppdaterad: 2011-12-21Bibliografiskt granskad
2. Industrial applications and properties of oxalate-degrading enzymes
Öppna denna publikation i ny flik eller fönster >>Industrial applications and properties of oxalate-degrading enzymes
2010 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Oxalate-degrading enzymes were investigated with focus on potential applications in the pulp and paper industry and in active packaging. Changes introduced to make the pulp and paper industry more environmentally friendly, such as recirculation of process-water streams and elementary chlorine free bleaching of pulp, have led to increasing problems with precipitation of calcium oxalate. The potential of using enzymes for degradation of oxalic acid in industrial bleaching filtrates was explored to find a way to decrease the problem.

The studies included chemical characterization and enzymatic treatments of 34 filtrates from kraft, mechanical, and sulfite pulping. Eight oxalate-degrading enzymes were included in the experiments. The treatments of the filtrates were affected by substances that inhibit oxalate-degrading enzymes. Multivariate data analysis, analytical treatment of filtrates with ion-exchange resins, and analysis of the effects of separate compounds on the enzyme activity were employed as tools to investigate inhibiting substances and groups of inhibitors. The experiments with ion-exchangers indicated that the inhibitors included anions, cations, as well as uncharged substances. Sulfite (≥1 mM) caused complete or almost complete inhibition of all oxalate-degrading enzymes so far examined, while the effects of chlorine oxyanions differed for the various enzymes investigated. A newly discovered oxalate decarboxylase was chosen for experiments performed directly in a mill producing mechanical pulp. The new enzyme degraded 70% of the oxalic acid in one hour, while the well-characterized oxalate decarboxylase from Aspergillus niger degraded <5% of the oxalic acid during the same period of time.

Oxalate decarboxylase from the white-rot basidiomycete fungus Trametes versicolor was purified by using chromatographic methods and characterized with gel electrophoresis and tandem mass spectrometry. Results indicate that it is a 69-kDa heavily glycosylated enzyme with optimal activity at pH 2.5.

Experiments designed to investigate the potential of using oxalate oxidase from barley in active packaging showed that it could be entrapped with retained catalytic activity in a latex-polymer matrix. Furthermore, the experiments indicate that oxalate oxidase can be used in active packaging either as an oxalic acid scavenger or as an oxygen scavenger.

Ort, förlag, år, upplaga, sidor
Karlstad: Karlstad University, 2010. s. 61
Serie
Karlstad University Studies, ISSN 1403-8099 ; 2010:21
Nyckelord
Oxalic acid, oxalate oxidase, oxalate decarboxylase, calcium oxalate, scaling, active packaging
Nationell ämneskategori
Kemi
Forskningsämne
Kemi
Identifikatorer
urn:nbn:se:kau:diva-5916 (URN)978-91-7063-313-3 (ISBN)
Disputation
2010-09-24, Ljungbergssalen, 21A 244, Karsltads universitet, Karlstad, 10:15 (Engelska)
Opponent
Handledare
Tillgänglig från: 2010-09-06 Skapad: 2010-06-18 Senast uppdaterad: 2011-11-03Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Övriga länkar

Förlagets fulltext

Personposter BETA

Winestrand, SandraJönsson, Leif J.

Sök vidare i DiVA

Av författaren/redaktören
Winestrand, SandraJönsson, Leif J.
Av organisationen
Avdelningen för kemi och biomedicinsk vetenskap
I samma tidskrift
Enzyme and microbial technology
Biomedicinsk laboratorievetenskap/teknologiMedicinsk bioteknologi (med inriktning mot cellbiologi (inklusive stamcellsbiologi), molekylärbiologi, mikrobiologi, biokemi eller biofarmaci)

Sök vidare utanför DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetricpoäng

doi
urn-nbn
Totalt: 282 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf