UWI Urban Water Interfaces (DFG research training group 2032)
H4 Redox gradients in natural and technical urban water systems: Population structure and physiological properties 
In this project, redox gradients in the hyporheic zone or the surface water-groundwater interface are being studied. This zone is known to have diverse redox conditions such as oxic, suboxic and anoxic and harbours correspondingly diverse microbial communities. All over the world, demographic changes are resulting in an increasing demand and consumption of pharmaceuticals and as a consequence, pharmaceutical residues released by wastewater treatment plants pose a threat to environmental processes, mainly in urban water systems.
The aim of this project is to explore microbial community structures and functional profiles of gradient biofilms of the hyporheic sediment in lab-scale sediment reactors. The biological transformation potentials of iopromide in lab-scale reactors containing natural sediment cores, should be enhanced. To achieve this aim, it has to be determined, if the pollutant-degrading bacteria can live on trace pollutants alone or if they require co-substrates or partner organisms to maintain their energy metabolism. Significant interactions like syntrophy and co-metabolism between organisms for determining degradation efficiency can then be identified. Analysis of the bacterial population structure in different layers of the sediment cores will be performed using Illumina® Sequencing. Monitoring the abundance of specific bacteria according to the dissipation of pollutants will be done by quantification of bacterial genes by real-time polymerase chain reaction. For visualization of the distribution and localization of bacteria on sediment particles fluorescence in-situ hybridisation will be used in combination with confocal laser scanning microscopy.
N1  Solid–water interface 
The aim of this thesis is to study the potential of both defined and natural biofilm communities to degrade (recalcitrant) pollutants such as paracetamol, diclofenac, carbamazepine and iodinated contrast media in urban water systems.
It focuses on the biofilms that are formed at various solid-water interfaces and consist of both aerobic and anaerobic subpopulations capable of promoting multiple degradation pathways and strategies. A variety of biofilm reactors and long standing experience in their operation and analysis are available. Different reactors will be used for testing organic removal rates and documenting the accumulation of microbial populations. The microbial populations will be examined by physiological tests and molecular methods (454 sequencing, FISH, CLSM, DGGE, qPCR).
In addition, a large collection of freshwater and iron bacteria already available in culture will be tested for their degradation potential. The aim is to evaluate if the pollutant-degrading organisms can live on trace pollutants alone or if they require cosubstrates to maintain their energy metabolism. We will also assess the significance of interactions (syntrophy, co-metabolism) between organisms for determining degradation efficiency.
We are especially interested in the extent that the pharmaceuticals are transformed to compounds which can be integrated into the pool of natural humic substances. After having identified the pollutant-degrading organisms, specific tools (FISH, qPCR) will be used to detect and quantify them in both laboratory reactors and natural biofilms.
Kontakt / ContactDr. rer. nat. Burga Braun
+ 49 30 314 73566
Room BH-N 615
e-mail query 
Kontakt / ContactMSc. Niranjan Mukherjee
+49 30 314 73752
Room BH-N 606
e-mail query