2.5 Analytical assay
Soluble metabolites (sugar and ethanol) were determined with a high performance liquid
chromatography (HPLC) system equipped with refractive index detection (RID, Waters 2414, USA). The
column used in the HPLC analysis was a ICSep ICE-COREGEL 87H3 column (Transgenomic, USA).
The mobile phase was 0.008 N H2SO4, with a flow rate of 0.4 mL/min. The injection sample volume was
20