Project leader: Gunnar Johansson
Ph.D student: Lars Hildén
Tel.: +46 18 471 10 00
Fax: +46 18 55 21 39

Ultrastructural studies of wood fibres with specific enzymes

Aim: The aim of the project is to increase the knowledge about the ultrastructure and composition of wood cells and wood fibres by using specific enzymes.

Background: The information about the ultrastructure of wood fibres is constantly increasing. The picture has drifted from simple models with only a few layers to models with a lamellar structure with more than 20 sublayers in one fibre. Several methods to reveal the composition of the individual layers exist. Usually lignin or hemicellulose is marked in some way. Cellulose is considered to be more difficult to mark. We think that well characterized wood degrading enzymes can be a useful tool for studying different layers and especially their cellulose parts. We will use both structurally and mechanically well defined cellulases from wood degrading fungi e.g. Phanerochaete chrysosporium and Trichoderma reesei. By first degrading a very thin piece of intact or delignified wood with one or more specific enzymes and then analyze both the wood slice and the solution surrounding it after incubation we hope to get information about what has been removed from where in the slice. The degradation patterns of the enzyme treated samples will be analyzed with electron microscopy, primarily SEM. The saccharide content of the surrounding solution will be analyzed using an HPLC-method. The project started 000103 and is planned to continue for four years.

Project description:
1. Determining the practical parameters of for studying fibres with enzymes (incubation times, necessary enzymes, photographic techniques etc.)

2. Investigate the cellulose content and orientation in wood fibres or
delignified wood.

3. Investigate the content and orientation of other substances, mainly lignin and hemicellulose, in wood fibres.

Project group:
Geoffrey Daniel, SLU
Lars Hildén, SLU/UU
Gunnar Johansson, UU
Thomas Nilsson, SLU

Competence linked to the group:
Christina Divne, UU
Gunnar Henriksson, KTH
Hongbin Henriksson, UU
Jiebing Li, KTH
Anu Nutt, UU
Sven Oscarsson, MDH
Göran Pettersson, UU
Jerry Ståhlberg, SLU/UU
Priit Veljamäe, UU
Jing Zhang, UU

Lars Hildén, Gunnar Johansson, Göran Pettersson, Anu Nutt, Priit Veljamäe
, Hongbin Henriksson and Jing Zhang are located at the Department of Biochemistry, Uppsala University, Uppsala:

Gunnar Henrikson and Jiebing Li are located at Pulp & Paper Chemistry &
Technology, division of Wood Chemistry, The Royal Institute ofTechnology,

Jerry Ståhlberg and Christina Divne are located at the Joint Structural
Biology Labs at the Biomedical Centre, Uppsala:

Sven Oscarsson is located at the Department of Biological and Chemical
Engineering, Mälardalen University, Eskilstuna: