title: Fed-batch like cultivation in a micro-bioreactor: screening conditions relevant for Escherichia coli based production processes.
abstract: OBJECTIVE
  Recombinant protein production processes in Escherichia coli are usually operated in fed-batch mode; therefore, the elaboration of a fed-batch cultivation protocol in microtiter plates that allows for screening under production like conditions is particularly appealing.
  
  
  RESULTS
  A highly reproducible fed-batch like microtiter plate cultivation protocol for E. coli in a micro-bioreactor system with advanced online monitoring capabilities was developed. A synthetic enzymatic glucose release medium was employed to provide carbon limited growth conditions without external substrate feed and the required buffer capacity to keep the pH value within 7 ± 1. Accurate process design allowed for cultivation up to cell densities of 10 g biomass l(-1) without any limitations in oxygen supply [dissolved oxygen (DO) level above 30 %]. In the micro-bioreactor system (BioLector) online monitoring of cell growth, DO and pH was performed. Furthermore, the influence of the cultivation temperature, the applicability for different host strains as well as the transferability of results to lab-scale bioreactor cultivations was evaluated.
  
  
  CONCLUSIONS
  This robust microtiter plate cultivation protocol allows for screening of E. coli systems under conditions comparable to lab-scale bioreactor cultivations.
authors.affiliation: Austrian Centre of Industrial Biotechnology, Muthgasse 11, Vienna, 1190 Austria.
authors.forename: Csilla
authors.initials: C
authors.lastname: Toeroek
authors.affiliation: Austrian Centre of Industrial Biotechnology, Muthgasse 11, Vienna, 1190 Austria.|Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Monika
authors.initials: M
authors.lastname: Cserjan-Puschmann
authors.affiliation: Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Karl
authors.initials: K
authors.lastname: Bayer
authors.affiliation: Austrian Centre of Industrial Biotechnology, Muthgasse 11, Vienna, 1190 Austria.|Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria.
authors.forename: Gerald
authors.initials: G
authors.lastname: Striedner
keywords: BioLector; Escherichia coli; Fed-batch mode; Microtiter plate; Strain screening