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Biochemical modification of wood components
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
2006 (English)Licentiate thesis, comprehensive summary (Other scientific)
Abstract [en]

The degradation of cellulose found in wood is one of the most important degradation processes for the carbon flux on earth. The degradation is performed by microorganisms that typically use enzymes. Since the cellulose in wood is crystalline and embedded in other polymers, making it inaccessible and durable, the enzymatic methods of cellulose degradation is also complex.

In this thesis, the action of some of these enzymes, called cellulases, have been studied both fundamentally and for industrial purposes. By using model cellulose films and a quartz crystal microbalance it was found that endoglucanases not only depolymerize but also swell model cellulose films. Most probably, this contributes to the synergy seen between endoglucanases and exoglucanases.

When an pulp fibers were pre--treated with endoglucanases and beaten subsequently, the fibers became more swollen than reference fibers. The effects of beating enzyme pre--treated fibers were investigated, indicating that endoglucanases improves the fiber/fiber interaction but also alters the behavior of the fibers in the beating process to become more susceptible to the beating.

The second part of the thesis has been focused on the use of an albino fungi in order to decrease the amount of wood extractives in wood chips prior to thermo mechanical pulp production. The fungus decreased the most troublesome component, the triglycerides, by more than 90 percent in two weeks without any detrimental effects on pulp properties. On the contrary, pulp strength and optical properties were improved.

Place, publisher, year, edition, pages
Stockholm: KTH , 2006. , 54 p.
Series
Trita-FPT-Report, ISSN 1652-2443 ; 2006:33
National Category
Paper, Pulp and Fiber Technology
Identifiers
URN: urn:nbn:se:kth:diva-4171OAI: oai:DiVA.org:kth-4171DiVA: diva2:11050
Presentation
2006-11-24, STFI-salen, KTH, Drottning Kristinas väg 61, Stockholm, 10:00
Opponent
Supervisors
Note
QC 20101117Available from: 2006-11-16 Created: 2006-11-16 Last updated: 2010-11-17Bibliographically approved
List of papers
1. The action of fungal cellulases studied using model cellulose films and a quartz crystal microbalance
Open this publication in new window or tab >>The action of fungal cellulases studied using model cellulose films and a quartz crystal microbalance
(English)Manuscript (Other academic)
Identifiers
urn:nbn:se:kth:diva-6357 (URN)
Note
QC 20101117Available from: 2006-11-16 Created: 2006-11-16 Last updated: 2010-11-17Bibliographically approved
2. Endoglucanase treatment of cellulose fibers improves the fiber/fiber interaction, but weakens the fiber strength
Open this publication in new window or tab >>Endoglucanase treatment of cellulose fibers improves the fiber/fiber interaction, but weakens the fiber strength
(English)Manuscript (Other academic)
Identifiers
urn:nbn:se:kth:diva-6358 (URN)
Note
QC 20101117Available from: 2006-11-16 Created: 2006-11-16 Last updated: 2010-11-17Bibliographically approved
3. Controlled seasoning of scots pine chips using an albino strain of ophiostoma
Open this publication in new window or tab >>Controlled seasoning of scots pine chips using an albino strain of ophiostoma
Show others...
2006 (English)In: Journal of Industrial and Engineering Chemistry, ISSN 1226-086X, Vol. 45, no 7, 2374-2380 p.Article in journal (Refereed) Published
Abstract [en]

Traditional seasoning of wood chips normally results in significant yield losses and brightness reduction due to the uncontrolled action of microorganisms. Techniques for reduction of the amount of wood extractives with minimal yield and brightness loss are therefore of interest for the pulp and paper industry. To study a biotechnological approach for reduction of wood extractives, wood chips from sapwood of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) were treated with a commercial albino strain of the sap stain fungus Ophiostoma piliferum. During 2 weeks of controlled seasoning, the content of wood extractives decreased by approximately 40% for Scots pine and 25% for Norway spruce, where the triglyceride contents were degraded to a greater degree. Thermomechanical pulps were produced from untreated and pretreated pine chips. The properties of these pulps and corresponding laboratory sheets were investigated. The pretreated pulps showed less shortened fibers, lower amounts of triglycerides, and enhanced strength properties. The mechanisms behind these effects are discussed. Furthermore, the ability of the albino Ophiostoma piliferum to displace mould growth from wood chips was investigated in a series of experiments. It was concluded that the fungus should preferably be inoculated on fresh chips in order to repress mould growth.

Keyword
Degradation, Growth kinetics, Microorganisms, Paper and pulp industry, Pulp, Wood
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-6359 (URN)10.1021/ie0512136 (DOI)000236715600025 ()2-s2.0-33646437244 (Scopus ID)
Note
QC 20100906Available from: 2006-11-16 Created: 2006-11-16 Last updated: 2010-09-06Bibliographically approved

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Citation style
  • apa
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  • Other locale
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Output format
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