Table 1 Overview of dynamic fed-batch experiments

FB1

Glycerol

Batch on glycerol–step-wise decrease of q_{s glycerol}: 0.338–0.063–0.054–0.029–0.014–0.005 g g⁻¹ h⁻¹

Determination of strain physiological parameters

Characterization of recombinant expression profile

FB2

Glycerol

Batch on glycerol–repression phase on glycerol (q_s = 0.29 g g⁻¹ h⁻¹)–de-repression phase on glycerol (q_s = 0.035 g g⁻¹ h⁻¹)

Mimic optimized industrial process comprising of three phases

FB3

Sorbitol

Batch on sorbitol–step-wise increase of q_{s sorbitol}:

0.033–0.060–0.127–0.176–0.197 g g⁻¹ h⁻¹

Determination of strain physiological parameters

Characterization of recombinant expression profile

Glycerol pulse at a final concentration of 10 g L⁻¹ at highest q_{s sorbitol}

q_s in presence of both substrates

FB4

Mixed feed

Batch on glycerol–repression phase on glycerol (q_s = 0.33 g g⁻¹ h⁻¹)–de-repression phase on glycerol (q_s = 0.054 g g⁻¹ h⁻¹)–mixed-feed: glycerol (q_s = 0.054 g g⁻¹ h⁻¹) and sorbitol (q_s = 0.070 g g⁻¹ h⁻¹)–mixed-feed: glycerol (q_s = 0.026 g g⁻¹ h⁻¹) and sorbitol (q_s = 0.015 g g⁻¹ h⁻¹)

Analyze physiology and productivity in mixed feed environment

FB5

Mixed feed

batch on glycerol– repression phase on glycerol (q_s = 0.33  g⁻¹ h⁻¹)–mixed-feed: glycerol (q_s = 0.040  g⁻¹ h⁻¹) and sorbitol (q_s = 0.055 g g⁻¹ h⁻¹)

Verify increased STY in mixed feed environment

FB6

Mixed feed

batch on glycerol–repression phase on glycerol

(q_s = 0.23 g g⁻¹ h⁻¹)–mixed-feed: glycerol (q_s = 0.026 g g⁻¹ h⁻¹) and sorbitol (q_s = 0.027 g g⁻¹ h⁻¹)–mixed-feed: glycerol (q_s = 0.026 g g⁻¹ h⁻¹) and sorbitol (q_s = 0.061 g g⁻¹ h⁻¹)

Verify increased STY in mixed feed environment

Identification of q_{s glycerol}/q_{s sorbitol} ratio allowing highest productivity and STY