Background

According to scientific estimates, there are around 10³⁰ archaea and bacteria all over the world, which make substantial contributions to the material cycles of our planet.

The multitude of microorganisms includes around four million species, but only ten thousand of these species are available as pure cultures to date.

Regarding the biology as well as the biochemical and biotechnological potential of most of the microorganisms there is a large knowledge gap, which we aim to decrease within this project.

 

Cultivation of aquatic microorganisms

As a multidisciplinary team, we want to develop a transportable bioreactor that can simulate the specific conditions for microorganisms from aquatic habitats. With the help of this system, uncultivated microorganisms are to be isolated from groundwater and drinking water, the deep terrestrial biosphere and from the water column of the ocean.

All of these aquatic habitats share the prevailing low nutrient concentrations and the specific occurrence of previously uncultivated groups of microorganisms.

 

Groundwater and drinking water

Groundwater is the most important resource for drinking water production in Germany and 70% of the distributed drinking water comes from groundwater and spring water. In addition, groundwater is an important part of the water cycle and habitat for a large number of organisms as an ecological compartment.

The natural microbal community of water provides an important basis for the hygienic safety of drinking water. Yet surprisingly little is known about the microbiological community in groundwater and drinking water.

 

Terrestrial habitats of the deep biosphere

The continental underground is home of around 30% of the total number of prokaryotes on earth and these ecosystems often also contain a complex biocenosis with several hundred different organisms that occur in over 100 different phyla.

These organisms harbor a large genetic repertoire, some of which have a very diverse biotechnological application potential. For example, in CPR from the deep biosphere, CRISPR systems were found that were much better organized than the systems previously investigated and thus showed new possibilities in the editing of the human genome.

However, the majority of these organisms and their physiology have so far remained little studied due to the more difficult sampling compared to ecosystems in the critical zone of the earth.

 

Water column of the ocean

Our oceans cover around 70% of our earth and are a central part of the global ecosystem. Due to the depth and the associated physical forces, the oceans are difficult to access and their exploration requires costly ship expeditions and the use of highly specialized underwater technologies. Through interacting geological, chemical, physical and, above all, microbiological processes, the oceans influence the climate system, the global cycle of matter and the usability for humans.

However, we still know too little about the biogeochemical mechanisms and the microorganisms involved in order to determine precise material balances and to predict the possible influences of global climate change.

 

Reactors for the cultivation of microorganisms

Bioreactors for cultivating microorganisms are widely used in industry and in many areas of the life sciences. Usually these systems are operated with high microorganism densities and substrate concentrations in order to achieve the maximum metabolic performance of selected organisms. Accordingly, commercially available systems are rarely suitable for the cultivation of oligotrophic microorganisms. However, it is precisely the use of culture media with low nutrient concentrations that has led to a considerable increase in the cultivation efficiency and diversity of aquatic microorganisms in various studies.

Different, individually designed bioreactors for the cultivation of new types of microorganisms are described, which mostly continuously deliver nutrients in low concentration through continuous operation and promote the selective growth of oligotrophic microorganisms.