Strains used in this study are listed in Table 1. E. coli DH5α was used for cloning experiments and (−)-α-bisabolol production. BL21(DE3) and MG1655 strains were used to compare effects of different host strains on the production and toxicity of (−)-α-bisabolol. E. coli strains were grown in Luria Bertani (LB) medium (10 g/L tryptone, 5 g/L yeast extract, and 5 g/L NaCl) for cloning experiments and (−)-α-bisabolol production. To produce (−)-α-bisabolol in E. coli, we used various media at 30 °C and 200 rpm; terrific broth (TB) medium (12 g/L enzymatic casein digest, 24 g/L yeast extract, 9.4 g/L K2HPO4, and 2.2 g/L KH2PO4), 2xYT medium (16 g/L tryptone, 10 g/L yeast extract, and 5 g/L NaCl), and M9 minimal medium (6.78 g/L Na2HPO4, 3 g/L KH2PO4, 0.5 g/L NaCl, 1 g/L NH4Cl, 0.241 g/L MgSO4, 0.0111 g/L CaCl2, and 0.1 g/L thiamine). M9 minimal medium was supplemented with 4 g/L of glucose. Ampicillin (100 μg/mL), chloramphenicol (34 μg/mL), or isopropyl β-d-1-thiogalactopyranoside (IPTG) as required.Table 1List of strains, plasmids, and primers used in this studyNameDescriptionRefsStrains DH5α F − , Φ80lacZ·ΔM15·ƒ(lacZYA−argF)U169 deoR recA1 endA1 hsdR17(rk−, mk+) phoA supE44 thi-1 gyrA96 relA1 Enzynomics MG1655F−, λ−, ilvG −, rfb-50, rph1ATCC 700926 BL21(DE3)BL21 F−, dcm ompT hsdS (rB- mB-) gal λ(DE3)EnzynomicsPlasmids pSSN12DidipSTV28 containing mvaK1, mvaD, mvaK2 of Streptococcus pneumoniae, and idi of E. coli  pPROLar.APlac/ara-1 expression vector, Kanr, p15A oriClontech pTrc99APtrc expression vector, Ampr, lacIq, pBR322 oriGE Healthcare pTSN-MrBBSpTrc99A containing MrBBS of Matricaria recutita This study pPR-IspApPROLar.A containing ispA of E. coli This study pTSN-MrBBS-IspApTSN-MrBBS containing ispA of E. coli This study pSNApSTV28 containing mvaK1, mvaK2, and mvaD of S. pneumoniae, idi of E. coli, and mvaE and mvaS, of Enterococcus faecalis  pSNA-MrBBSpSNA containing MrBBS of M. recutita This study pSNA-MrBBS-IspApSNA-MrBBS containing ispA of E. coli This studyPrimersa Bis-IF aggttaaaccatgagcacactgagcgtcagThis study Bis-IR cgactctagattagactatcatcggatgtaThis study Bis-VF gatagtctaatctagagtcgacctgcaggcThis study Bis-VR gtgtgctcatggtttaacctcctgtgtgaaattgttatcThis study IspAI-F ggtaccccatatggactttccgcagcaactThis study IspAI-R tgcctctagattatttattacgctggatgaThis study IspAV-F taataaataatctagaggcatcaaataaaaThis study IspAV-R gaaagtccatatggggtacctttctcctctThis study IspAop-IF acatccgatgatagtctaatattcattaaagaggagaaagThis study IspAop-IR tgcatgcctgcaggtcgactctagattatttattacgctgThis studyOverlap region for Gibson Assembly is underlined aPrimer sequences are indicated in the 5′–3′ direction