title: Parallel substrate feeding and pH-control in shaking-flasks.
abstract: An intermittent feeding system for shaking-flasks was developed to close the gap between batch operated shaking-flasks and fed-batch operated as well as pH-controlled stirred tank reactors. A precise syringe pump was connected via a substrate distribution system to individual 2/2-way miniature valves, one for each of up to 16 shaking-flask. The shaking-flasks were equipped with pH-probes. A process computer controls the intermittent feeding of substrates by tracking predefined individual feeding profiles as well as the base (or acid) addition for individual pH-control of the shaking-flasks. Higher concentrations of aerobic cells with higher cellular activities were achieved in fed-batch operated and pH-controlled shaking-flasks as compared to the conventional batch operation. Physiological effects of an intermittent feeding were studied in a stirred tank reactor with a recombinant E. coli strain, which expressed the GDP-mannose-pyrophosphorylase enzyme under the control of the lac-promoter.
authors.affiliation: Institute of Biochemical Engineering, Munich University of Technology, Boltzmannstr. 15, 85748, Garching, Germany
authors.forename: D
authors.initials: D
authors.lastname: Weuster-Botz
authors.forename: J
authors.initials: J
authors.lastname: Altenbach-Rehm
authors.forename: M
authors.initials: M
authors.lastname: Arnold