title: Minireactor-based high-throughput temperature profiling for the optimization of microbial and enzymatic processes.
abstract: BACKGROUND
  Bioprocesses depend on a number of different operating parameters and temperature is one of the most important ones. Unfortunately, systems for rapid determination of temperature dependent reaction kinetics are rare. Obviously, there is a need for a high-throughput screening procedure of temperature dependent process behavior. Even though, well equipped micro-bioreactors are a promising approach sufficient temperature control is quite challenging and rather complex.
  
  
  RESULTS
  In this work a unique system is presented combining an optical on-line monitoring device with a customized temperature control unit for 96 well microtiter plates. By exposing microtiter plates to specific temperature profiles, high-throughput temperature optimization for microbial and enzymatic systems in a micro-scale of 200 μL is realized. For single well resolved temperature measurement fluorescence thermometry was used, combining the fluorescent dyes Rhodamin B and Rhodamin 110. The real time monitoring of the microbial and enzymatic reactions provides extensive data output. To evaluate this novel system the temperature optima for Escherichia coli and Kluyveromyces lactis regarding growth and recombinant protein production were determined. Furthermore, the commercial cellulase mixture Celluclast as a representative for enzymes was investigated applying a fluorescent activity assay.
  
  
  CONCLUSIONS
  Microtiter plate-based high-throughput temperature profiling is a convenient tool for characterizing temperature dependent reaction processes. It allows the evaluation of numerous conditions, e.g. microorganisms, enzymes, media, and others, in a short time. The simple temperature control combined with a commercial on-line monitoring device makes it a user friendly system.
authors.affiliation: AVT-Chair for Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kunze
authors.affiliation: AVT-Chair for Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Lattermann
authors.affiliation: AVT-Chair for Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Diederichs
authors.affiliation: Department of Chemistry (Organic and Bioorganic Chemistry), University of Graz, Heinrichstraße 28/II, 8010 Graz, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kroutil
authors.affiliation: AVT-Chair for Biochemical Engineering, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Büchs
keywords: High-throughput screening; Microtiter plate; On-line monitoring; Optical measurement; Temperature optimum