Presentation of different cultivation modes used in this study. (A) Scheme of the two reactor setups used in the study, a standard fed-batch in a stirred tank reactor and a fed-batch performed in a STR-PFR two-compartment reactor system with feeding of the glucose feed solution into the entrance of the PFR. (B-D) illustrate typical cultivation data of E. coli W3110 with the different types of cultivation applied in this study. (B) Glucose limited fed-batch cultivation with continuous feed of glucose at a constant feed rate in a single STR (reference). (C) Same as (B) but with a downshift of the DOT by a simultaneous decrease of stirrer speed and aeration rate. (D) Cultivation in a STR-PFR system with feeding of the glucose feed solution into the lower part of the PFR. The graphs show the experimental data for cell density (OD600), glucose concentration, and the DOT. All analyses from the STR-PFR system were performed from samples collected by the standard sampling valve in the STR. Zero hours indicates the time of the feed start. The analyses in (C) reflect samples taken from the STR compartment. All cultivations were started with a glucose concentration of 40 g L-1.