IspA overexpression and batch fermentation of engineered E. coli. a Improvement of (−)-α-bisabolol production in E. coli DH5α transformed with pSNA-MrBBS-IspA compared with DH5α harboring the pSNA-MrBBS plasmid. Cells were cultivated in TB medium containing 10 g/L glycerol at 30 °C for 48 h using two-phase culture without the addition of IPTG. Data represent averages from three replicate cultures; error bars show SD, b effects of IPTG addition on (−)-α-bisabolol production in E. coli DH5α harboring pSNA-MrBBS-IspA. Culture conditions were the same as in Fig. 6a, except for the addition of IPTG. IPTG was added to each culture to a final concentration of 0.05 mM when the OD600 reached 0.5. Data represent averages from three replicate cultures; error bars show SD, c time profile of batch fermentation of E. coli DH5α with pSNA-MrBBS-IspA in TB medium containing 10 g/L of glycerol as carbon source at 30 °C, n-dodecane was overlaid up to 20% (v/v) of culture volume to continuously extract (−)-α-bisabolol from the culture broth during fermentation. d Time profile of batch fermentation of E. coli DH5α with pSNA-MrBBS-IspA in TB medium containing 10 g/L of glycerol as carbon source at 25 °C. n-Dodecane was overlaid up to 20% (v/v) of culture volume to continuously extract (−)-α-bisabolol from the culture broth during fermentation