Fig. 8

Time course of 1-butanol production in the absence of inducer and antibiotics. Strain ΔldhA ΔfrdBC ΔadhE Δpta transformed with the best combination (FRE _ackA ::atoB-adhE2-crt-hbd, FRE _adhE ::ter, FRE _adhE ::fdh) was used in this study. To examine if similar production efficiency could be maintained in the absence of antibiotics, two of the better performing 1-butanol production conditions were tested here: (1) anaerobic switch at OD₆₀₀ of 0.4 and (2) high-density fermentation by concentrated cell as indicated in the figure legend. Identical cultivation and production procedure to the ones described in Fig. 7 were used. Samples were taken every 12 h (anaerobic switch at exponential phase) or 24 h (high-density culture) anaerobically with adjustment of culture pH and feeding of glucose. “Time” indicates time since anaerobic switch