Fig. 3
Two-step pulsed fed-batch cultivations in glucose minimal medium with an aerobic batch phase and a microaerobic production phase of E. coli W/445_Ediss under a high oxygen (DO 0–1%) and b low oxygen (constant stirrer and aeration). c E. coli W ∆ldhA ∆adhE ∆pta ∆frdA/445_Ediss with low oxygen production phase and d E. coli W ∆ldhA ∆adhE ∆pta ∆frdA ∆pykA/445_Ediss with low oxygen production phase. Glucose concentration was monitored throughout the cultivation in regular intervals. Once glucose was completely consumed, an appropriate amount of a glucose-medium solution was pulsed to the culture to restore a glucose concentration of 50 g l−1. Each cultivation was carried out in duplicates; only one cultivation is shown for better visualization (duplicate is shown in Additional file 2: Figure S3)