2.5. Cultivation in the bioREACTOR 48

The bioREACTOR 48 (2mag AG) ¹⁶ was combined with a Tecan Freedom Evoۚ platform (Tecan Group Ltd., Männedorf, Switzerland) for process automation, e.g. sampling. Samples were collected in 1.5 mL reaction tubes and cooled down to 4°C. For monitoring and control of process parameters, the bioREACTOR 48 LabView program and iLab software provided by infoteam Software AG were used ¹⁷, ¹⁸. The gas exchange in the headspace was assured by a continuous supply of sterile filtered pressured air through the head unit of the reactor. Temperature was maintained at 30°C. A calibration of the pH and DOT sensor spots of the disposable vessels was performed according to the bioREACTOR 48 manual. For inoculation of the individual reaction vessels of the reactor, a preculture of K. lactis 21B7 was centrifuged and the cells were resuspended in EnPresso Y Defined medium resulting in a final OD ₆₀₀ of 2. Eight parallel vessels were filled with 12 mL of this cell suspension and different concentrations of glucose releasing Reagent A were added (4, 7, 10, and 15 U L⁻¹). The cultivations were performed in duplicates.