Dr. Katja Bühler

University

Dortmund

department: BCI, Laboratory of Chemical Biotechnology

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TU Dortmund University, Department of Biochemical and Chemical Engineering, Laboratory of Chemical Biotechnology, Technical Enzymology Group

Research interests

This research group focuses on the evaluation of novel, alternative reactor and reaction concepts for the application in biotechnology. In vitro as well as in vivo approaches are evaluated.

Biofilms
One of the main bottlenecks in continuous bioprocesses is the stability of the biocatalyst. Therefore, long-term industrial applications are rare. This project focuses on biofilms as new designer biocatalysts, with the final goal of large-scale applications in fine chemical bioprocesses. So far, the industrial use of biofilms was mainly restricted to wastewater treatment and off-gas cleaning. However, their beneficial aspects of self-immobilization, increased tolerance against toxic substrates and products, and the possibility to reach high cell-densities are our motivation to employ biofilms also for biotransformations and think of new biofilm reactor concepts.

In vitro biocatalysis
In addition to whole cell applications we also apply isolated enzymes in biocatalysis. Our main focus lies on oxygenases and dehydrogenases. These enzymes depend on cofactors like NAD(P)H and/or FADH making a successful application in a biocatalytic process dependent on an efficient cofactor regeneration system. By developing cutting-edge cofactor regeneration systems based on electrochemical or enzymatic means combined with biocatalyst engineering approaches we aim at designing efficient and competitive process concepts for the use oxidoreductases in vitro.

Protein expression and purification
In order to efficiently optimize biocatalytic processes, it is necessary to know as much as possible about the applied biocatalyst. Therefore the enzyme of interest is mostly expressed recombinant in Escherichia coli, Pseudomonas sp. or yeast in order to achieve a sufficient amount of protein after the purification procedure. Protein purification is mainly based on chromatographic procedures, but also heat treatment and inclusion bodies are utilized for this task, depending on the enzyme. The purified proteins are investigated focussing on kinetic parameters as well as stability. Clarification of enzyme structure is achieved in collaboration with other groups via crystallization or NMR studies.

To find out more, visit the website of the Technical Enzymology Group.

Students (co-)supervised

Karsten Lang
Karolin Schmutzler