Photo of Annika Björn

Annika Björn

Associate Professor, Docent

Increased methane production and process stability in biogas reactors

We investigate the potential for increased biogas process efficiency within the limits set by both technical and microbial demands. The main goal is to further develop our understanding on the role of trace elements to promote biogas production as such, but also their role as possible effectors on the rheology of reactor liquids coupled to the microbial formation of viscosity-active organic compounds. Also, to deepen the knowledge about hydrolytic reactions and define underutilized substrates within AD by characterizing the type of complex structures that remains in digester residues from a number of different, defined, AD-processes. 

Through the establishment of the UASB (Upflow Anaerobic Sludge Blanket) technology and CSTR (completely stirred tank reactors) with sludge recirculation, we intend to create conditions for methane production from paper and pulp industry (PMI) wastewater equivalent to about 100 MNm3 methane per year. Earlier estimates are 17 Nm3. In addition to this energy output is saved large amounts of electricity and oil by reducing aeration needs in water treatment and minimization of sludge incineration.

Supplementation of trace elements to optimize biogas production 

Part of my research specifically investigates the role of trace elements in rheology dynamics, foaming potential and microbial response for efficient biogas production.  It involves use of a suite of trace elements to enhance biogas production and process stability. Analysis of inorganic and organic complexation chemistry of trace elements, together with rheological characterization and molecular biological methodologies, to elucidate effects on the rheology and microbial community structures and activity.

Improved hydrolysis as a means to increase the overall degradability of organic material

Hydrolysis has in many cases been shown to be the rate limiting step for anaerobic digestion (AD) of complex polymers, and studies have also shown that much of the complex, less available, organic structures are in many cases only partly digested during AD. To obtain a more efficient utilization of all types of complex AD-substrates the efficiency of the hydrolysis therefore needs to be increased. Our research intend to deepen the knowledge about hydrolytic reactions and define underutilized substrates within AD by characterizing the type of complex structures that remains in digester residues from a number of different, defined, AD-processes (screening). The results from the chemical screening will then be used as a base for laboratory experiments, aiming to increase the rate of hydrolysis and the fraction/part of the material hydrolyzed for at least three of these processes from a microbial point of view. Action taken to increase the hydrolysis efficiency can thus be: Changed process configuration (re-circulation of digester material, phase separation etc.), addition/ enrichment of selected hydrolytic enzymes, adjustments in substrate composition, adjustment of nutrient/trace element levels or changes in dosing strategies.

Research activities in connection with the school development program KNUT

Energy issues consequences for the environment and your health are important context and the significance of those increases. Information about them in basic education is crucial for all people for the opportunity to participate in a common culture. At the same needs of the future expertise recruited and trained for excellence. The school development project "KNUT" address these educational purposes with a focus on better goal achievement through improved teaching, which is based on the energy issue management. A research effort that draws attention to students 'and teachers' perspectives selection of content and what influences young people's choice of education is therefore crucial issues. I work with these issues through research efforts based on an interactive research approach, which involves cooperation between stakeholders, targeting and change management based on science and proven experience.

KNUT (Knowledge, Natural Science, Out-door learning and Technology)



Thuane Mendes Anacleto, Betina Kozlowsky-Suzuki, Annika Björn (Fredriksson), Sepehr Shakeri Yekta, Laura Shizue Moriga Masuda, Vinicius Peruzzi de Oliveira, Alex Enrich Prast (2024) Methane yield response to pretreatment is dependent on substrate chemical composition: a meta-analysis on anaerobic digestion systems Scientific Reports, Vol. 14, Article 1240 Continue to DOI
Helena Rodrigues Oliveira, Betina Kozlowsky-Suzuki, Annika Björn (Fredriksson), Sepehr Shakeri Yekta, Cristiane Fonseca Caetano, Erika Flavia Machado Pinheiro, Humberto Marotta, Joao Paulo Bassin, Luciano Oliveira, Marcelo de Miranda Reis, Mario Sergio Schultz, Norberto Mangiavacchi, Viridiana Santana Ferreira-Leitao, Daniel Oluwagbotemi Fasheun, Fernanda Geraldo Silva, Igor Taveira, Ingrid Roberta de Franca Soares Alves, Julia Castro, Juliana Velloso Durao, Juliana Guimaraes, Mariana Erthal Rocha, Marina Tomasini, Pedro Vitor de Oliveira Martins, Rogerio Presciliano, Stella Buback dos Santos, Tamires Marques Faria, Tarcisio Correa, Thiago de Nuno Mendes Pery de Linde, Fernanda Abreu, Alex Enrich Prast (2024) Biogas potential of biowaste: A case study in the state of Rio de Janeiro, Brazil Renewable energy, Vol. 221, Article 119751 Continue to DOI


Luka Safaric, Annika Björn (Fredriksson), Bo H Svensson, David Bastviken, Sepehr Shakeri Yekta (2023) Rheology, Micronutrients, and Process Disturbance in Continuous Stirred-Tank Biogas Reactors Industrial & Engineering Chemistry Research, Vol. 62, p. 17372-17384 Continue to DOI


Tong Liu, Xiaoxiao Li, Sepehr Shakeri Yekta, Annika Björn, Bo-Zhong Mu, Laura Shizue Moriga Masuda, Anna Schnürer, Alex Enrich Prast (2022) Absence of oxygen effect on microbial structure and methane production during drying and rewetting events Scientific Reports, Vol. 12, Article 16570 Continue to DOI
Ebba Perman, Anna Schnürer, Annika Björn, Jan Moestedt (2022) Serial anaerobic digestion improves protein degradation and biogas production from mixed food waste Biomass and Bioenergy, Vol. 161, Article 106478 Continue to DOI


Biogas Research



  • 2007
    PhD in Environmental Studies, Linköping University

  • 1997
    M.Sc. Chemistry,  Linköping University


Research Area Coordinator for process and technology development,
the Biogas Research Center (BRC).


  • Environmental Science
  • Thematic science and science.
  • Chemistry
  • Chemical biology
  • Biology
  • Engineering and science subjects for future teachers


About the Department