(−)-α-Bisabolol is a naturally occurring sesquiterpene alcohol that exhibits antibacterial activity . This property would be a hurdle for the use of E. coli as a terpenoid production host . Therefore, we examined the suitability of three different E. coli strains [DH5α, MG1655, and BL21(DE3)] for (−)-α-bisabolol production by conducting growth assays in LB in the presence of various concentrations of (−)-α-bisabolol (Fig. 2). After 3 h of cultivation (mid-log phase), the growth of BL21(DE3) significantly decreased by 1 and 5 g/L (−)-α-bisabolol (Fig. 2a). The growth of MG1655 was not affected by (−)-α-bisabolol at concentrations of 1 or 5 g/L (Fig. 2a). The growth of DH5α slightly decreased at (−)-α-bisabolol concentration of 5 g/L, but growth was not affected by 1 g/L (−)-α-bisabolol (Fig. 2a). This result was corroborated with CFU measurements for each culture. As expected, DH5α showed the best tolerance to (−)-α-bisabolol whereas BL21(DE3) formed no colonies on the solid LB medium (Fig. 2b). These results are consistent with a previous study showing that of five different B- and K-type E. coli strains (MG1655, DH5α, S17-1, XL1-Blue, and BL21), DH5α is the best producer of the β-carotene (C40) terpenoid . In addition, E. coli DH5α has been used for production of retinol , farnesol , and protoilludene . We concluded that E. coli DH5α is suitable as a host for (−)-α-bisabolol production and it was used for all subsequent experiments.Fig. 2Growth inhibition of E. coli strains by exogenous (−)-α-bisabolol. a Time course of growth profile. b CFU measurement. Cells were grown in LB liquid medium and different amounts of (−)-α-bisabolol were added at the beginning of cultivation. Samples were taken for measurement of optical density at 600 nm (OD600). Samples for CFU measurement were taken at early stationary phase (indicated by an arrow). Mean values of two independent experiments are given for the CFU measurement