Quantification of farnesene

At the end of the cultivation, the dodecane overlay was harvested by centrifugation at 4000 rpm for 3 min. Similarly, samples were collected during cultivations in bioreactors. Analysis was performed using a Focus GC-FID (Thermo Fisher Scientific) equipped with a ZB-50 column (Phenomenex, Torrance, CA, USA) as described previously with minor modifications [31]. The initial temperature was held at 50 °C for 1.5 min and then increased to 170 °C at a rate of 15 °C/min. After keeping the temperature constant for another 1.5 min, it was raised at the same rate to 300 °C and held for 3.0 min. The inlet temperature was set to 250 °C and 2 μL sample were injected in splitless mode. The base temperature of the flame was set to 300 °C. Farnesene was quantified using external calibration with trans-β-farnesene as analytical standard (≥90%, Sigma Aldrich). Samples were diluted in hexane and patchoulol (≥99%, a kind gift from Firmenich, Geneva, Switzerland) was added as internal standard. Concentrations of farnesene are stated based on the volume of the aqueous phase of the medium (mg/L_aq).