Fig. 4

IME improved tolerance to inhibitors in lignocellulose-derived feedstocks. a–c IME had improved tolerance to inhibitors existing in the hydrolysate of lignocellulose (HMF, levulinic acid and vanillic acid). Growth curves were recorded in MOPS + 2% glucose medium with different inhibitors in a clear bottom 96-well plate at 37 °C, pH 7.0. d IME showed increased cell mass and glucose consumption with addition of representative inhibitors existing in the hydrolysate of lignocellulose. Both control and IME strains were cultivated in MOPS + 2% (w/v) glucose mineral salt medium containing 16 mM HMF (2 g/L), 43 mM levulinic acid (5 g/L), and 6 mM vanillic acid (0.5 g/L) in shake flasks at 37 °C and an initial pH of 7.0. Error bars indicate standard deviation of at least three biological replicates. HMF, hydroxymethylfurfural