Agilent 7683

Metabolites were analyzed by GC-TOF/MS (Waters Corp., USA) as described previously50 . The 1 μL derivatized sample was injected by Agilent 7683 autosampler into GC (Agilent 6890) which was equipped with DB-5MS column (30 m × 0.25 mm × 0.25 μm, J&W Scientific, Folsom, CA). The oven temperature was programmed as: 70 °C for 2 min, then increased to 290 °C (5 °C/min), holding for 3 min. The ion source temperature and ionization current were 250 °C and 40 μA, respectively. The mass scan range was 50–800 m/z. Peak detection, deconvolution, and peak quantification were performed using Masslynx software 4.151 . Metabolites were identified by comparing their mass fragmentation patterns with NIST mass spectral library52 . The area of each acquired peak was normalized against the internal standard and dry cell weight for calculating the relative abundance. Multivariate data analysis was preformed by principal-components analysis (PCA)53 and hierarchical cluster analysis (HCA)54 to view the relative differences in the metabolites concentrations among diverse conditions.

One microliter sample was injected by Agilent 7683 autosampler into Agilent 6890 GC which was equipped with a fused-silica capillary column (30 m×0.25 mm i.d., 0.25 µm DB-5MS, J&W Scientific, Folsom, CA). The injector temperature was 260°C, and ions were generated by a 70 eV electron beam at an ionization current of 40 µA. The column effluent was introduced into the ion source (250°C) of TOF/MS. The mass scan range was 50–800 m/z.
For GC-TOF/MS analysis of taxadiene, the temperature gradient program started at 200°C for 3 min followed by heating the column at 4°C/min to 270°C, and a final constant hold at 270°C for 2 min. The taxadiene was identified by the mass fragment m/z 272, 122, and 107 according to the identification of purified sample (Fig. S2 in File S1). For GC-TOF/MS analysis of intracellular metabolites, the oven temperature was programmed as: 70°C for 2 min, then increased to 290°C (5°C/min), holding for 3 min.

The polymer contents and monomer compositions of synthesized PHAs were determined by gas chromatography (GC) or GC-MS (Supplementary Methods)^{34 (link)}. The collected cells were washed three times with distilled water and then lyophilized for 24 h. The PHAs in lyophilized cells were converted into corresponding hydroxymethyl esters by acid-catalyzed methanolysis^{33 (link)}. The resulting methyl esters were analysed by GC (Agilent 6890 N, Agilent) equipped with Agilent 7683 automatic injector, flame ionization detector, and a fused silica capillary column (ATTM-Wax, 30 m, ID 0.53 mm, film thickness 1.20 μm, Alltech). Polymers were extracted from the cells by chloroform extraction method^{35 (link),36 (link)}. Polymer content is defined as the weight percentage of polymer concentration to dry cell concentration (wt% of dry cell weight). The structure, molecular weights, and thermal properties of the polymers were determined by nuclear magnetic resonance spectroscopy, gel permeation chromatography, and differential scanning calorimetry, respectively (Supplementary Methods)^{8 (link),9 (link)}.

The compounds present in the EO were determined qualitatively and quantitatively using a gas chromatograph (GC) (model 6890N series, Agilent Technologies, Santa Clara, CA, USA) according to the procedures described by Valarezo, et al. (2021) [39 (link)], with minimal modifications to some parameters. In the case of qualitative analyses, the GC was equipped with a mass spectrometer (type quadrupole) detector (MS) (model Agilent series 5973 inert, Agilent Technologies, Santa Clara, CA, USA) and, for quantitative analyses, GC was coupled to a flame ionization detector (FID). In both cases, an automatic injector (Agilent 7683, Agilent Technologies, Santa Clara, CA, USA) in split mode and a nonpolar column DB-5 ms were used. The samples are prepared with a ratio of 1/100 (v/v) of EO/DCM and then injected with a split ratio of 1:50. The temperature ramp was 50 °C for 3 min, then 2.5 °C/min until 210 °C, and 3 min at this temperature. The injector temperature was 210 °C and 250 °C for both detectors. The retention index (IR) was determined based on the comparison of retention times of the EO compounds and of the aliphatic hydrocarbons of standard injection under the same conditions. The compounds were identified based on a comparison of mass spectrum data and IRs with those published in the literature [40 ,41 ].