In this work, to understand the mechanism of ethanol tolerance of C. thermocellum more deeply, we adopted systematic metabolomics to compare the intracellular and extracellular polar-/fatty-phase metabolites in C. thermocellum WT
and ET strains in the absence and presence of 3% (v/v) exogenous ethanol (designated as ET0 and ET3, respectively) using nuclear magnetic resonance (NMR), gas chromatography-mass spectroscopy (GC-MS), and ion chromatography (IC)