Determination of metabolite concentration
The concentration of glucose, glycerol, ethanol, acetic and succinic acid was determined using a Surveyor Plus liquid chromatograph (Thermo Fisher Scientific, Waltham, MA) equipped with a refraction index and a photodiode array detector (Surveyor RI Plus and Surveyor PDA Plus, respectively) on a 300 × 7.7 mm HyperREZ™ XP Carbohydrate H + (8 μm particle size) column and guard (Thermo Fisher Scientific). The column was maintained at 50 °C and 1.5 mM H2SO4 was used as the mobile phase at a flow rate of 0.6 mL min− 1. Prior to injection in duplicate, the samples were filtered through 0.22 μm pore size nylon filters (Micron Analitica) and diluted 10-fold.