2 5 dmf

Escherichia coli strain MC4100, grown as described by Deplanche et al. (2012) (link), was harvested in mid-logarithmic phase (OD₆₀₀ of 0.7–1.0) by centrifugation (9,000 × g, 15 min, 4°C), washed three times (20 mM MOPS-NaOH buffer, pH 7.0) and routinely stored as a concentrated suspension overnight (4°C). The cell dry weight was estimated from a previously determined OD/dry weight conversion.
Commercial metal salts (Na₂PdCl₄ and RuCl₃) were from Sigma-Aldrich, as were 5 wt% Pd and 5 wt% Ru on carbon catalysts and commercial 5-HMF (≥99%) and 2,5-DMF (99%).

5-HMF (≥99%) and 2,5-DMF (99%) were from Sigma Aldrich. Catalytic transfer hydrogenation reactions used a 100 mL stainless steel reactor (Parr; external temperature and stirring controllers). For a typical reaction the reactor was charged with 0.05 M 5-HMF in tetrahydrofuran (25 mL) and 0.05 g catalyst, sealed, purged with H₂ (5 bar) and charged with 50 bar H₂. The reaction (260 °C; 2 h; 700 rpm) was stopped on ice (time as determined by prior tests) and the mixture was filtered (Whatman; 8 µm). 5-HMF and 2,5-DMF were analysed by GC Shimadzu 2010; FID detector and ZB-SemiVolatile column: 30 m × 0.25 mm × 0.50 µm; Waters GCT Premier time-of-flight mass spectrometer (Micromass, Manchester, UK) with a ZB-SemiVolatile-MS column; injection volume 1 µl; injector temperature 300 °C; detector temperature; 300 °C, inlet pressure 100 KPa; split ratio of 100:1, with He carrier gas at a flow rate of 1 mL/min). An initial column temperature (50 °C) was held for 5 min, the temperature was ramped (16.6 °C/min) to 133.3 °C, held for 1.5 min, ramped to 300 °C and held for 3.5 min. For GC-MS analysis, Waters MassLynx software (version 4.1) was used to operate the GC-TOFMS system. The source temperature was 200 °C and electron energy was 70 eV. 5-HMF conversion and DMF yield were based on standards. Other products were not quantified.