Aggregation in syntrophic communities

Last changed: 18 February 2021

The long-term ambition of this project is to understand the role of aggregation of syntrophic microorganisms that can inspire development of highly productive biotechnological systems for biogas formation.

In the biogas system, thousands of different microorganisms work in a cooperative manner to convert the organic material to methane (biogas). Of particular importance is syntrophic microbial interactions, which have shown to underpin the success of some of the most productive biotechnological systems, including the conversion of protein-rich wastes to biogas. These syntrophic microorganisms cooperate to degrade acids but there are barriers and challenges to these organisms reaching their full potential, which restricts productivity and stability in the biogas process. Build-up of acids (e.g. acetate, propionate) and lowering of renewable energy yields are common consequences of restricted syntrophic activity, which in the long-term cause full-scale facilities to operate below capacity.

Getting closer together!

The syntrophic cooperation depends on transfer of intermediate compounds between the syntrophic (cross-feeding) microorganism and this transfer has been identified as the rate limiting step for the acid degradation. Past scientific discoveries suggest that transfer of intermediates in syntrophic cooperation can be accelerated by reduced cell-to-cell distance between the syntrophic microorganisms.

In this project called "SYNAG" we will generate a complete view of syntrophic aggregate formation. This will enable us to study the processes that underlie aggregate formation and evaluate how it is affected by various surrounding environmental factors. The long-term overarching goal of SYNAG is to form a general model for aggregate development in syntrophic communities and to create a basis for novel process-design that will support key microorganisms and improve the productivity in biogas processes.

The rate of acid degradation depends on the hydrogen uptake for which diffusion is rate limiting
The rate of acid degradation depends on the hydrogen uptake for which diffusion is rate limiting
If the distance between bacteria that degrade acids and bacteria that consume hydrogen becomes smaller, the rate of degradation increases.
By lowering the distance between the cells, the acid degradation will be faster
Factors that can affect aggregation and thus how quickly acids are degraded can be found in the surrounding environment for the bacteria, e.g. temperature, pH or toxic substances. There may also be purely microbial factors such as a "glue effect" between certain bacterial cells. There may also be added factors such as nanoparticles or nutrients.
Factors that can affect aggregation and thus how quickly acids are degraded can be found in the surrounding environment for the bacteria, e.g. temperature, pH or toxic substances. There may also be purely microbial factors such as a "glue effect" between certain bacterial cells. There may also be added factors such as nanoparticles or nutrients.
Illustration of the upscaling of an improved the biogas process
Illustration of the upscaling of an improved the biogas process

This project is supported by the European Research Council (ERC) with the Starting grant No. 948138 and the by Swedish Research Council (VR) with the grant No. 2019-03846
Project start: 1 March 2021    Project duration: 5 years

 


Facts:

At SLU we work with the whole biogas chain. An unique feature for our research is that we answer questions about both energy generation and waste treatment. We have our own biogas plant as well as top modern laboratories.


Contact

Maria Westerholm Maria.Westerholm@slu.se

Associate professor, PhD
Swedish University of Agricultural Sciences
Department of Molecular Sciences

Page editor: Henrik.Hansson@slu.se