Background and activities

I am a research professor and adjunct professor at the Department of Biotechnology and Food Science and Nobipol. My research has been focused on microbiology/biochemistry/biotechnology on industrial microorganisms, both basic and applied projects.  I teach parts of Biochemistry II and the PhD course BT8120.

Areas of speciality

  • Understand and control the biosynthesis of alginate in Pseudomonas fluorescens and Azotobacter vinelandii
  • Studies of alginate-modifying enzymes
  • Design enzymes with new properties.
  • Develop microorganisms (bacteria and thraustochytrids) producing feed ingredients, especially DHA and EPA
  • Study the effect of bacterially produced surfactants, proteins and polysaccharides on the floatability of nanosized mineral particles.
  • A. vinelandii encystment
  • The collection of Actinomycetes from the Trondheim fjord
  • Tutoring master and PhD students

Background and expertise

I took my master degree in 1987, and PhD in 1994, both at the University of Trondheim, AVH. From 1987 to 2004 I was employed at SINTEF as a researcher/senior researcher. From 2005 I have been working at NTNU.

My work has been within industrial biotechnology. In most cases the motivation has been to understand the bacteria and the properties of pathways and enzymes in order to ultimately construct bacteria that may produce various products (proteins or metabolites) at levels sufficent for an industrial process. I have now expertise on cloning, homologous recombination and tailoring of genetic tools in different bacteria. Another aspect has been production, purification and characterization of enzymes. the projects have also involved genome mining and the use of other databases to find genes coding for a desired activity or to better understand metbolic pathways.

Scientific, academic and artistic work

Displaying a selection of activities. See all publications in the database













  • Gimmestad, Martin; Steigedal, Magnus; Ertesvåg, Helga; Moreno, Soledad; Christensen, Bjørn Erik; Espín, Guadalupe; Valla, Svein. (2006) Identification and characterization of an Azotobacter vinelandii type I secretion system responsible for export of the AlgE-Type mannuronan C-5-epimerases. Journal of Bacteriology. vol. 188 (15).


  • Bakkevig, Karianne; Sletta, Håvard; Gimmestad, Martin; Aune, Randi; Ertesvåg, Helga; Degnes, Kristin; Christensen, Bjørn Erik; Ellingsen, Trond Erling; Valla, Svein. (2005) Role of the Pseudomonas fluorescens alginate lyase (AlgL) in clearing the periplasm of alginates not exported to the extracellular environment. Journal of Bacteriology. vol. 187 (24).


  • Bjerkan, Tonje Marita; Bender, Carol; Ertesvåg, Helga; Drabløs, Finn; Fakhr, Mohamed K.; Preston, Lori A.; Skjåk-Bræk, Gudmund; Valla, Svein. (2004) The pseudomonas syringae genome encodes a combined mannuronan C-5-epimerase and O-acetylhydrolase, which strongly enhances the predicted gel-forming properties of alginates. Journal of Biological Chemistry. vol. 279 (28).


  • Gimmestad, Martin; Sletta, Håvard; Ertesvåg, Helga; Bakkevig, Karianne; Jain, Sumita; Suh, Sang-jin; Skjåk-Bræk, Gudmund; Ellingsen, Trond E.; Ohman, Dennis E.; Valla, Svein. (2003) The Pseudomonas fluorescens AlgG protein, but not its mannuronan C-5-epimerase activity, is needed fro alginate polymer formation. Journal of Bacteriology. vol. 185 (12).