Mercator Research Center Ruhr (MERCUR):

Stress response in biofilms

Project partners:

TU Dortmund / Laboratory of Chemical Biotechnology:     

• Prof. Andreas Schmid
• Dr. Katja Bühler
• Dr. Babu Halan

University of Duisburg-Essen / Biofilm Centre - Molecular Enzyme Technology and Biochemistry (MEB)  and Aquatic Microbiology:

• Prof. Bettina Siebers
• Prof. Hans-Curt Flemming
• Dr. Jost Wingender
• Silke Jachlewski
• Jens Benninghoff

The goal of this project is to understand the response of archaeal and bacterial biofilms towards process related conditions relevant for the biotechnical production of chemical materials. Biofilms as new designer biocatalysts offer the advantages of enhanced tolerance to environmental stress factors and long-term stability, allowing for the conversion of biologically challenging compounds and continuous processes. Two model organisms are investigated: the mesophilic bacterium Pseudomonas sp. strain VLB120ΔC (TU Dortmund) and the archaeon Sulfolobus acidocaldarius (University of Duisburg-Essen). The focus is on the influence of solvents involved in biotransformation processes, which are most often toxic to the biocatalyst, impairing process performance especially of planktonic cultures. When exposed to such solvents, the intrinsic response of the cells in the biofilms is multifaceted (Figure 1). Upon exposure to environmental stress, bacteria are known to enter into a viable but non-culturable (VBNC) state. An important aspect will be to investigate the influence of solvent stress on the vitality and physiological activity of biofilms and the possible induction of the VBNC state of the biofilm cells. The objective is to identify and optimize the conditions for the use of biofilms in solvent-dependent biotechnical applications.

Figure 1: Conceptual theme of the project.

To analyze solvent exposed biofilms, we focus on non-invasive, time-resolved and on-line methodologies based on confocal laser scanning microscopy and flow cell cultivation systems. In addition, biochemical assays (e.g. Lowry assay, phenol-sulfuric acid method) for the analysis of whole biofilms and their extracellular polymeric substances (EPS) as important structural and functional components of the biofilm matrix are widely applied in this study.

This project is financed by Mercator Research Center Ruhr (Mercur) which primarily supports the research cooperation among the regional universities.