title: Fully automated single-use stirred-tank bioreactors for parallel microbial cultivations.
abstract: Single-use stirred tank bioreactors on a 10-mL scale operated in a magnetic-inductive bioreaction block for 48 bioreactors were equipped with individual stirrer-speed tracing, as well as individual DO- and pH-monitoring and control. A Hall-effect sensor system was integrated into the bioreaction block to measure individually the changes in magnetic field density caused by the rotating permanent magnets. A restart of the magnetic inductive drive was initiated automatically each time a Hall-effect sensor indicates one non-rotating gas-inducing stirrer. Individual DO and pH were monitored online by measuring the fluorescence decay time of two chemical sensors immobilized at the bottom of each single-use bioreactor. Parallel DO measurements were shown to be very reliable and independently from the fermentation media applied in this study for the cultivation of Escherichia coli and Saccharomyces cerevisiae. The standard deviation of parallel pH measurements was pH 0.1 at pH 7.0 at the minimum and increased to a standard deviation of pH 0.2 at pH 6.0 or at pH 8.5 with the complex medium applied for fermentations with S. cerevisiae. Parallel pH-control was thus shown to be meaningful with a tolerance band around the pH set-point of +/- pH 0.2 if the set-point is pH 6.0 or lower.
authors.affiliation: Lehrstuhl für Bioverfahrenstechnik, Technische Universität München, Boltzmannstrasse 15, 85748 Garching, Germany. a.kusterer@lrz.tum.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Kusterer
authors.forename: Christian
authors.initials: C
authors.lastname: Krause
authors.forename: Klaus
authors.initials: K
authors.lastname: Kaufmann
authors.forename: Matthias
authors.initials: M
authors.lastname: Arnold
authors.forename: Dirk
authors.initials: D
authors.lastname: Weuster-Botz
mesh_terms: D001331:Automation; D019149:Bioreactors; D015374:Biosensing Techniques; D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods; D018929:Cell Culture Techniques / Q000379:methods; D004867:Equipment Design; D004926:Escherichia coli / Q000378:metabolism; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology / Q000379:methods; D010100:Oxygen / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013050:Spectrometry, Fluorescence / Q000379:methods; D013997:Time Factors
chemical_list: D010100:Oxygen