{tab=Research} Anita Sellstedt in the KBC cafeteriaPhoto: Fredrik Larsson

The aim of our research is to study energy production in microorganisms. The research covers several projects, of which the three main projects will briefly be presented below.

Hydrogen metabolism of Frankia

Nitrogen fixation occurs in Frankia both in free-living as well as in symbioses and may contribute as much as a quarter of the total yearly biologically fixed nitrogen globally in terrestrial ecosystem.

The most important recent achievement in the Frankia research field is the sequencing of three Frankia genomes. We were able to show that there are large differences in the genome sizes. Frankia EANpec1 was found to have the largest genome with 9.0 Mb, while Frankia ACN14a had an intermediate size of 7.5 Mb and Frankia HFPCcI3 was the smallest at 5.4 Mb. These numbers were correlated with geographical origin, host plant distribution and repeated sequences, such as IS. Our findings open up a new era in Frankia research, yielding possibilities to explore the molecular biology of Frankia.

An inevitable source of energy-inefficiency in the nitrogen-fixation process is the evolution of hydrogen; as much as 25% of the in vitro electron-flow through nitrogenase goes to hydrogen evolution. Some nitrogen-fixing systems have dealt with this problem of energy loss through evolving an extra enzyme, called uptake hydrogenase, which is very common in Frankia.

Round vesicles of the bacterium Frankia are shown on the left side and elongated cells of Chalara parvispora on the right side. Left: Light micrograph of the bacterium Frankia showing vesicles; right: Light micrograph of our isolate of Chalara parvispora

Cyanobacteria in association with boreal mosses

We were able to discover that cyanobacteria live in association with feather mosses in the boreal area. We also discovered that they are able of fixing nitrogen and thereby contributing to the N status of that ecosystem.

Heterotrophic production of lipids by algae

Algae are commonly autotrophic carbon dioxide fixing prokaryotes. They are also able of storing different compounds under a variety of conditions. This year a Thesis from my laboratory revealed that some microalgae are able to use glycerol as a carbon source under growing in heterotrophic conditions. Interestingly, a microalgae isolated in the lab and originating from Umeå area has this trait and also accumulated significant amounts of lipids under this condition.


Key Publications

  • Leul M, Normand P, Sellstedt A (2009). The phylogeny of uptake hydrogenases. Int Microbiol. 12(1): 23-28.
  • Normand et al., (2007). Genome structure reflects host biogeography in three plant symbionts Frankia sp. strains. Genome Research, 17, 7-15.
  • Mohapatra A, Leul M, Mattsson U, Sellstedt A (2004). A hydrogen-evolving enzyme is present in Frankia R43. FEMS Microbiol.Lett.236: 235-240
  • DeLuca TH, O Zackrisson, M-C Nilsson, A Sellstedt (2002). Quantifying nitrogen fixation in feather moss carpets. Nature. 419: 917-920.
  • Nzayisenga JC, Eriksson K, Sellstedt A. 2018. Mixotrophic and heterotrophic production of lipids and carbohydrates by a locally isolated microalga using wastewater as growth medium. Bioresource Technology 257: 260-265.
{tab=Team}

{tab=CV A. Sellstedt}
  • Since 2002: Professor at the Department of Plant Physiology, Umeå University, Umeå
  • 1991: Senior lecturer, Umeå university
  • 1990: Associate Professor/Docent, Umeå university
  • 1989: Post Doc, Australia
  • 1985: PhD, Plant Physiology, Umeå University
{tab=Publications}
  2024 (1)
Frankia [NiFe] uptake hydrogenases and genome reduction: different lineages of loss. Pawlowski, K., Wibberg, D., Mehrabi, S., Obaid, N. B., Patyi, A., Berckx, F., Nguyen, H., Hagen, M., Lundin, D., Brachmann, A., Blom, J., Herrera-Belaroussi, A., Abrouk, D., Pujic, P., Hahlin, A., Kalinowski, J., Normand, P., & Sellstedt, A. FEMS Microbiology Ecology,fiae147. October 2024.
Frankia [NiFe] uptake hydrogenases and genome reduction: different lineages of loss [link]Paper   doi   link   bibtex   abstract  
  2023 (1)
Presence and activity of nitrogen-fixing bacteria in Scots pine needles in a boreal forest: a nitrogen-addition experiment. Bizjak, T., Sellstedt, A., Gratz, R., & Nordin, A. Tree Physiology, 43(8): 1354–1364. August 2023.
Presence and activity of nitrogen-fixing bacteria in Scots pine needles in a boreal forest: a nitrogen-addition experiment [link]Paper   doi   link   bibtex   abstract  
  2021 (1)
Metabolomic Study of Heterotrophically Grown Chlorella sp. Isolated from Wastewater in Northern Sweden. Nzayisenga, J. C., & Sellstedt, A. Molecules, 26(9): 2410. April 2021.
Metabolomic Study of Heterotrophically Grown Chlorella sp. Isolated from Wastewater in Northern Sweden [link]Paper   doi   link   bibtex   abstract   2 downloads  
  2020 (6)
Bioethanol production from four abundant Indian agricultural wastes. Harinikumar, K. M., Kudahettige-Nilsson, R. L., Devadas, A., Holmgren, M., & Sellstedt, A. Biofuels, 11(5): 607–613. July 2020.
Bioethanol production from four abundant Indian agricultural wastes [link]Paper   doi   link   bibtex   2 downloads  
Candidatus Frankia nodulisporulans sp. nov., an Alnus glutinosa-infective Frankia species unable to grow in pure culture and able to sporulate in-planta. Herrera-Belaroussi, A., Normand, P., Pawlowski, K., Fernandez, M. P., Wibberg, D., Kalinowski, J., Brachmann, A., Berckx, F., Lee, N., Blom, J., Pozzi, A. C., Fournier, P., Bethencourt, L., Dubost, A., Abrouk, D., & Sellstedt, A. Systematic and Applied Microbiology, 43(6): 126134. November 2020.
Candidatus Frankia nodulisporulans sp. nov., an Alnus glutinosa-infective Frankia species unable to grow in pure culture and able to sporulate in-planta [link]Paper   doi   link   bibtex  
Effects of light intensity on growth and lipid production in microalgae grown in wastewater. Nzayisenga, J. C., Farge, X., Groll, S. L., & Sellstedt, A. Biotechnology for Biofuels, 13(1): 4. December 2020.
Effects of light intensity on growth and lipid production in microalgae grown in wastewater [link]Paper   doi   link   bibtex   abstract  
More than protection: the function of TiO $_{\textrm{2}}$ interlayers in hematite functionalized Si photoanodes. Kawde, A., Annamalai, A., Sellstedt, A., Uhlig, J., Wågberg, T., Glatzel, P., & Messinger, J. Physical Chemistry Chemical Physics, 22(48): 28459–28467. 2020.
More than protection: the function of TiO $_{\textrm{2}}$ interlayers in hematite functionalized Si photoanodes [link]Paper   doi   link   bibtex   abstract  
More than protection: the function of TiO2 interlayers in hematite functionalized Si photoanodes. Kawde, A., Annamalai, A., Sellstedt, A., Uhlig, J., Wågberg, T., Glatzel, P., & Messinger, J. Physical Chemistry Chemical Physics, 22(48): 28459–28467. December 2020. Publisher: The Royal Society of Chemistry
More than protection: the function of TiO2 interlayers in hematite functionalized Si photoanodes [link]Paper   doi   link   bibtex   abstract  
Screening Suitability of Northern Hemisphere Algal Strains for Heterotrophic Cultivation and Fatty Acid Methyl Ester Production. Nzayisenga, J. C., Niemi, C., Ferro, L., Gorzsas, A., Gentili, F. G., Funk, C., & Sellstedt, A. Molecules, 25(9): 2107. April 2020.
Screening Suitability of Northern Hemisphere Algal Strains for Heterotrophic Cultivation and Fatty Acid Methyl Ester Production [link]Paper   doi   link   bibtex   abstract  
  2019 (1)
A microstructured p-Si photocathode outcompetes Pt as a counter electrode to hematite in photoelectrochemical water splitting. Kawde, A., Annamalai, A., Sellstedt, A., Glatzel, P., Wågberg, T., & Messinger, J. Dalton Transactions, 48(4): 1166–1170. 2019.
A microstructured p-Si photocathode outcompetes Pt as a counter electrode to hematite in photoelectrochemical water splitting [link]Paper   doi   link   bibtex   abstract  
  2018 (2)
Mixotrophic and heterotrophic production of lipids and carbohydrates by a locally isolated microalga using wastewater as a growth medium. Nzayisenga, J. C., Eriksson, K., & Sellstedt, A. Bioresource Technology, 257: 260–265. June 2018.
Mixotrophic and heterotrophic production of lipids and carbohydrates by a locally isolated microalga using wastewater as a growth medium [link]Paper   doi   link   bibtex  
Photo-electrochemical hydrogen production from neutral phosphate buffer and seawater using micro-structured p-Si photo-electrodes functionalized by solution-based methods. Kawde, A., Annamalai, A., Amidani, L., Boniolo, M., Kwong, W. L., Sellstedt, A., Glatzel, P., Wågberg, T., & Messinger, J. Sustainable Energy & Fuels, 2(10): 2215–2223. 2018.
Photo-electrochemical hydrogen production from neutral phosphate buffer and seawater using micro-structured p-Si photo-electrodes functionalized by solution-based methods [link]Paper   doi   link   bibtex   abstract  
  2016 (2)
Adaptability of Trametes versicolor to the lignocellulosic inhibitors furfural, HMF, phenol and levulinic acid during ethanol fermentation. Kudahettige Nilsson, R. L., Holmgren, M., Madavi, B., Nilsson, R. T., & Sellstedt, A. Biomass and Bioenergy, 90: 95–100. July 2016.
Adaptability of Trametes versicolor to the lignocellulosic inhibitors furfural, HMF, phenol and levulinic acid during ethanol fermentation [link]Paper   doi   link   bibtex  
Expression of fungal acetyl xylan esterase in Arabidopsis thaliana improves saccharification of stem lignocellulose. Pawar, P. M., Derba-Maceluch, M., Chong, S., Gómez, L. D., Miedes, E., Banasiak, A., Ratke, C., Gaertner, C., Mouille, G., McQueen-Mason, S. J., Molina, A., Sellstedt, A., Tenkanen, M., & Mellerowicz, E. J. Plant Biotechnology Journal, 14(1): 387–397. January 2016.
Expression of fungal acetyl xylan esterase in <i>Arabidopsis thaliana</i> improves saccharification of stem lignocellulose [link]Paper   doi   link   bibtex  
  2015 (2)
Biomass‐Based Energy Production. Arshadi, M., & Sellstedt, A. In Clark, J., & Deswarte, F., editor(s), Introduction to Chemicals from Biomass, pages 249–284. Wiley, 1 edition, February 2015.
Biomass‐Based Energy Production [link]Paper   doi   link   bibtex   abstract  
Genome Sequence of the Atypical Symbiotic Frankia R43 Strain, a Nitrogen-Fixing and Hydrogen-Producing Actinobacterium. Pujic, P., Bolotin, A., Fournier, P., Sorokin, A., Lapidus, A., Richau, K. H., Briolay, J., Mebarki, F., Normand, P., & Sellstedt, A. Genome Announc, 3(6). November 2015. Edition: 2015/11/27
Genome Sequence of the Atypical Symbiotic Frankia R43 Strain, a Nitrogen-Fixing and Hydrogen-Producing Actinobacterium [link]Paper   doi   link   bibtex   abstract  
  2013 (1)
Aspects of nitrogen-fixing Actinobacteria , in particular free-living and symbiotic Frankia. Sellstedt, A., & Richau, K. H. FEMS Microbiology Letters, 342(2): 179–186. May 2013.
Aspects of nitrogen-fixing <i>Actinobacteria</i> , in particular free-living and symbiotic <i>Frankia</i> [link]Paper   doi   link   bibtex  
  2012 (2)
Characterization of Bioethanol Production from Hexoses and Xylose by the White Rot Fungus Trametes versicolor. Kudahettige, R. L., Holmgren, M., Imerzeel, P., & Sellstedt, A. BioEnergy Research, 5(2): 277–285. June 2012.
Characterization of Bioethanol Production from Hexoses and Xylose by the White Rot Fungus Trametes versicolor [link]Paper   doi   link   bibtex  
Hydrogen yield from a hydrogenase in Frankia R43 at different levels of the carbon source propionate. Kosawang, C., Kudahettige, R. L., Resman, L., & Sellstedt, A. Journal of Environmental Management, 95: S365–S368. March 2012.
Hydrogen yield from a hydrogenase in Frankia R43 at different levels of the carbon source propionate [link]Paper   doi   link   bibtex  
  2009 (2)
Nitrogen fixation in mixed Hylocomium splendens moss communities. Zackrisson, O., DeLuca, T. H., Gentili, F., Sellstedt, A., & Jäderlund, A. Oecologia, 160(2): 309–319. May 2009.
Nitrogen fixation in mixed Hylocomium splendens moss communities [link]Paper   doi   link   bibtex  
The phylogeny of uptake hydrogenases in Frankia. Leul, M., Normand, P., & Sellstedt, A. International Microbiology: The Official Journal of the Spanish Society for Microbiology, 12(1): 23–28. March 2009.
doi   link   bibtex   abstract  
  2008 (1)
Identification of white-rot and soft-rot fungi increasing ethanol production from spent sulfite liquor in co-culture with Saccharomyces cerevisiae. Holmgren, M., & Sellstedt, A. Journal of Applied Microbiology, 105(1): 134–140. July 2008.
Identification of white-rot and soft-rot fungi increasing ethanol production from spent sulfite liquor in co-culture with <i>Saccharomyces cerevisiae</i> [link]Paper   doi   link   bibtex  
  2007 (5)
Ecosystem controls on nitrogen fixation in boreal feather moss communities. DeLuca, T. H., Zackrisson, O., Gentili, F., Sellstedt, A., & Nilsson, M. Oecologia, 152(1): 121–130. April 2007.
Ecosystem controls on nitrogen fixation in boreal feather moss communities [link]Paper   doi   link   bibtex  
Frankia ? the friendly bacteria ? infecting actinorhizal plants. Sellstedt, A., Normand, P., & Dawson, J. Physiologia Plantarum, 130(3): 315–317. July 2007.
Frankia ? the friendly bacteria ? infecting actinorhizal plants [link]Paper   doi   link   bibtex  
Modulation of Frankia alni ACN14a oxidative stress response: activity, expression and phylogeny of catalases. Santos, C. L., Vieira, J., Sellstedt, A., Normand, P., Moradas-Ferreira, P., & Tavares, F. Physiologia Plantarum, 130(3): 454–463. July 2007.
Modulation of Frankia alni ACN14a oxidative stress response: activity, expression and phylogeny of catalases [link]Paper   doi   link   bibtex  
Reactive oxygen species in legume and actinorhizal nitrogen-fixing symbioses: the microsymbiont?s responses to an unfriendly reception. Tavares, F., Santos, C. L., & Sellstedt, A. Physiologia Plantarum, 130(3): 344–356. July 2007.
Reactive oxygen species in legume and actinorhizal nitrogen-fixing symbioses: the microsymbiont?s responses to an unfriendly reception [link]Paper   doi   link   bibtex  
The organization, regulation and phylogeny of uptake hydrogenase genes in Frankia. Leul, M., Normand, P., & Sellstedt, A. Physiologia Plantarum, 130(3): 464–470. July 2007.
The organization, regulation and phylogeny of uptake hydrogenase genes in Frankia [link]Paper   doi   link   bibtex  
  2006 (2)
Genome characteristics of facultatively symbiotic Frankia sp. strains reflect host range and host plant biogeography. Normand, P., Lapierre, P., Tisa, L. S., Gogarten, J. P., Alloisio, N., Bagnarol, E., Bassi, C. A., Berry, A. M., Bickhart, D. M., Choisne, N., Couloux, A., Cournoyer, B., Cruveiller, S., Daubin, V., Demange, N., Francino, M. P., Goltsman, E., Huang, Y., Kopp, O. R., Labarre, L., Lapidus, A., Lavire, C., Marechal, J., Martinez, M., Mastronunzio, J. E., Mullin, B. C., Niemann, J., Pujic, P., Rawnsley, T., Rouy, Z., Schenowitz, C., Sellstedt, A., Tavares, F., Tomkins, J. P., Vallenet, D., Valverde, C., Wall, L. G., Wang, Y., Medigue, C., & Benson, D. R. Genome Research, 17(1): 7–15. December 2006.
Genome characteristics of facultatively symbiotic Frankia sp. strains reflect host range and host plant biogeography [link]Paper   doi   link   bibtex  
Occurrence and characterisation of the hydrogen-evolving enzyme in Frankia sp. Mohapatra, A., Leul, M., Sandström, G., & Sellstedt, A. International Journal of Hydrogen Energy, 31(11): 1445–1451. September 2006.
Occurrence and characterisation of the hydrogen-evolving enzyme in Frankia sp. [link]Paper   doi   link   bibtex   abstract  
  2005 (4)
Biodiversity of Hydrogenases in Frankia. Leul, M., Mohapatra, A., & Sellstedt, A. Current Microbiology, 50(1): 17–23. January 2005.
Biodiversity of Hydrogenases in Frankia [link]Paper   doi   link   bibtex   abstract  
Measuring nitrogen fixation by Sesbania sesban planted fallows using 15N tracer technique in Kenya. Ståhl, L., Högberg, P., Sellstedt, A., & Buresh, R. J. Agroforestry Systems, 65(1): 67–79. October 2005.
Measuring nitrogen fixation by Sesbania sesban planted fallows using 15N tracer technique in Kenya [link]Paper   doi   link   bibtex   abstract  
Molecular characterization of uptake hydrogenase in Frankia. Leul, M., Mattsson, U., & Sellstedt, A. Biochemical Society Transactions, 33(1): 64–66. February 2005.
Molecular characterization of uptake hydrogenase in Frankia [link]Paper   doi   link   bibtex   abstract  
Physiological and molecular diversity of feather moss associative N-2-fixing cyanobacteria. Gentili, F., Nilsson, M. C., Zackrisson, O., DeLuca, T. H., & Sellstedt, A. Journal of Experimental Botany, 56(422): 3121–3127. December 2005. Place: Oxford Publisher: Oxford Univ Press WOS:000233491300011
doi   link   bibtex   abstract  
  2004 (2)
A hydrogen-evolving enzyme is present in Frankia sp. R43. Mohapatra, A., Leul, M., Mattsson, U., & Sellstedt, A. FEMS Microbiology Letters, 236(2): 235–240. July 2004.
A hydrogen-evolving enzyme is present in Frankia sp. R43 [link]Paper   doi   link   bibtex   abstract  
Nitrogen fixation increases with successional age in boreal forests. Zackrisson, O., DeLuca, T. H., Nilsson, M. C., Sellstedt, A., & Berglund, L. M. Ecology, 85(12): 3327–3334. December 2004. Place: Hoboken Publisher: Wiley WOS:000226297500014
doi   link   bibtex   abstract  
  2003 (1)
Laser-based micromanipulation for separation and identification of individual Frankia vesicles. Leitz, G., Lundberg, C., Fallman, E., Axner, O., & Sellstedt, A. Fems Microbiology Letters, 224(1): 97–100. July 2003. Place: Amsterdam Publisher: Elsevier Science Bv WOS:000184248400014
doi   link   bibtex   abstract  
  2002 (2)
Nickel Affects Activity More Than Expression of Hydrogenase Protein in Frankia. Mattsson, U., & Sellstedt, A. Current Microbiology, 44(2): 88–93. February 2002.
Nickel Affects Activity More Than Expression of Hydrogenase Protein in Frankia [link]Paper   doi   link   bibtex  
Quantifying nitrogen-fixation in feather moss carpets of boreal forests. DeLuca, T. H., Zackrisson, O., Nilsson, M., & Sellstedt, A. Nature, 419(6910): 917–920. October 2002. Bandiera_abtest: a Cg_type: Nature Research Journals Number: 6910 Primary_atype: Research Publisher: Nature Publishing Group
Quantifying nitrogen-fixation in feather moss carpets of boreal forests [link]Paper   doi   link   bibtex   abstract  
  2001 (2)
DNase-Resistant DNA in the Extracellular and Cell Wall-Associated Fractions of Frankia Strains R43 and CcI3. Tavares, F., & Sellstedt, A. Current Microbiology, 42(3): 168–172. March 2001.
DNase-Resistant DNA in the Extracellular and Cell Wall-Associated Fractions of Frankia Strains R43 and CcI3 [link]Paper   doi   link   bibtex   abstract  
Frankia KB5 Possesses a Hydrogenase Immunologically Related to Membrane-Bound [NiFe]-Hydrogenases. Mattsson, U., Johansson, L., Sandström, G., & Sellstedt, A. Current Microbiology, 42(6): 438–441. June 2001.
Frankia KB5 Possesses a Hydrogenase Immunologically Related to Membrane-Bound [NiFe]-Hydrogenases [link]Paper   doi   link   bibtex   abstract  
  2000 (2)
A simple, rapid and non-destructive procedure to extract cell wall-associated proteins from Frankia. Tavares, F., & Sellstedt, A. Journal of Microbiological Methods, 39(2): 171–178. January 2000.
A simple, rapid and non-destructive procedure to extract cell wall-associated proteins from Frankia [link]Paper   doi   link   bibtex   abstract  
Hydrogenase in Frankia KB5: Expression of and relation to nitrogenase. Mattsson, U., & Sellstedt, A. Canadian Journal of Microbiology, 46(12): 1091–1095. December 2000. Publisher: NRC Research Press
Hydrogenase in Frankia KB5: Expression of and relation to nitrogenase [link]Paper   doi   link   bibtex  
{tab=Svenska} Anita Sellstedt i KBC café

Det viktigaste framsteget på senare tid inom forskningen på Frankia och actinorhiza växter är utan tvekan sekvenseringen av tre Frankia-genom. Vi lyckades visa att det är en stor skillnad i storlek hos dessa tre genom. Hydrogenaserna tillhör en grupp, bestående av 13 enzymer som katalyserar vätgasomsättning, och vi har hitintills lyckats visa att även Frankia har ett hydrogenas med både upptags- och vätgasutvecklande funktion.

Frankia är en aktinomycet, en vanligt förekommande jordbakterie, som förutom att delta i vätgasmetabolism också har förmågan att fixera luftens kväve. Vid kvävefixeringen bildas också vätgas, som tyvärr här är en energikrävande biprodukt, som sänker effektiviteten för kvävefixeringen. Men vissa av kvävefixerande bakterie däribland Frankia har utvecklat vätgasoxiderande enzymer, upptagshydrogenas, som kan fånga upp vätgasen och göra den till energi för bakterien igen. Upptagshydrogenas är vanligt förekommande hos Frankia, som också har vätgasutvecklande funktion, som skulle kunna användas för vätgasproduktion.

Vår forskning på etanolproduktion från cellulosabaserad biomassa har visat att vi kan öka denna drastiskt med tillsats av två svampar: Chalara parvispora och Trametes versicolor.