Metabolite Profiling of Microbial Growth

Cell growth was monitored using UV-visible Spectrophotometer SU-2000 (OnLab Instruments). Maltose, glucose, xylose, xylitol, glycerol, acetate and ethanol were quantified by high performance liquid chromatography (Agilent 1200 Series HPLC system) equipped with a refractive index detector (Shimadzu, Japan) and an Bio-Rad Aminex HPX-87H organic acid analysis column (7.8 × 300 mm) which was maintained at 50 °C and used 0.05 mM sulfuric acids as mobile phase. The sample injection volume was 10 μL and the flow rate was 0.6 mL/min. Metabolites was detected by liquid chromatography-mass spectrometry/mass spectrometry system (Agilent 6460 series LC-MS/MS system) with Agilent XDC18 column (5 uM, 150 mm × 4.6 mm)36 (link). Di-n-butylammonium acetate (DBAA) and NaH¹³CO₃ were purchased from Sigma-Aldrich. Methanol was purchased from Fisher Scientific. The mobile phase was the mixture of solution A (water with 5 mM DBAA) and solution B (methanol with 5 mM DBAA) at the gradient shown in Table S6. The flow rate was 0.6 mL/min. The injection volume was 50 μL and the column temperature was 40 °C. The negative ion and selected multiple reactions monitoring (MRM) mode were used for MS detection. All experiments were conducted at least in triplicate, and the error bars in the figures denote the standard deviation from the means of independent experiments.