Microbial Ecology and Physiology (MEP)

Microbial Ecology and Physiology (MEP)

Forskningsgruppen Microbial Ecology and Physiology (MEP) ved NMBUs fakultet for kjemi, bioteknologi og matvitenskap, i november 2021.

About Microbial Ecology and Physiology (MEP)

Our research group «Microbial ecology and physiology (MEP) works with different aspects of environmental microbiology and microbial ecology. Our main focus is on microorganisms that drive the biogeochemical nitrogen cycle, which involves a number of processes in which nitrogen is transformed in different redox reactions. Some types of bacteria and archaea are capable of “fixing” nitrogen (N2) from the atmosphere and reduce it to ammonia, which can be used by most living organisms to make amino acids and proteins. When the organisms die, the organic nitrogen is degraded and the reactive nitrogen that is released will go through a series of processes and finally be released back to the atmosphere as nitrogenous gases. Most will be harmless N2, but some will be emitted as N2O, a potent greenhouse gas that also destroys the stratospheric ozone layer. The reduction of N2O to N2, the final step of the N-cycle, is therefore crucial.

The only known enzyme that can reduce N2O is the N2O reductase, found in several groups of bacteria and in some archaea. Our research has provided several crucial pieces of knowledge to the understanding of how denitrifying bacteria, which can respire nitrogen oxides when oxygen becomes scarce, regulate their production and reduction of N2O. Our studies include both basic and applied research and include all scales “from molecules to the field” or, in other words, from enzymes to complex microbial communities (microbiomes)” in soils and in engineered systems such as wastewaters and biogas fermenters.

A major mission that we have is to develop novel methods to mitigate N2O emissions from agricultural soils, which account for the main part of the anthropogenic emissions of this greenhouse gas globally. We are currently working on two approaches to manipulate the soil microbiome to become a sink for N2O. One is to enrich digestates, derived from biogas production, with N2O reducing bacteria, and we have very promising results for this so far. Another option is to inoculate legumes with bacteria (rhizobia) that not only increase their N2-fixation capacity but that are also strong sinks for N2O. One exciting and new track for our denitrification research is to use these organisms for single-cell protein production (project AnaPro). Our ongoing basic research projects aims to better understand how denitrifying organisms handle environmental stresses. Although many nuts and bolts of the regulatory networks involved in denitrification have been unraveled, the current knowledge is mostly based on laboratory studies of organisms growing under optimal conditions, while surprisingly little is known about the regulation of denitrification in bacteria living under natural conditions.

In the recently started project STARVOX we will study how starvation (lack of carbon substrate) and oxidative stress influences the regulation of denitrification in different bacteria, with a focus on effects on N2O emission. Another ongoing basic research project (N2Air) follows up our discovery that the negative correlation seen between soil pH and N2O emissions is due to the organisms having problems with producing functional N2O reductase in acidic environments (link) and dives deeper into the enzyme structure to determine if the problem lies in an inability of the bacteria to insert Cu ions into the active center of the enzyme when pH is below 6.   

Watch a short Euronews film about of our research  

The research group Microbial Ecology and Physiology (MEP) works with different aspects of environmental microbiology and microbial ecology.

The research group Microbial Ecology and Physiology (MEP) works with different aspects of environmental microbiology and microbial ecology.

Photo
Pawel Lycus

News from MEP

News from MEP

News from MEP

Read the latest news from the research group MEP; publications, projects and MSc theses.

About the MEP-group

Contact information