Figure 4
Time course of fermentation by the YPH499ΔILV1 transformants. ΔILV1-emp indicates the strain harboring the pATP426 empty vector and ΔILV1-kAI indicates the strain harboring the pATP423 empty vector and pATP426-kivd-ADH6-ILV2 plasmid for enhancing isobutanol biosynthesis. ΔILV1-kAI-PMsM and ΔILV1-kAI-MAE1 indicate the strains harboring pATP426-kivd-ADH6-ILV2 and pATP423-PMsM, and pATP426-kivd-ADH6-ILV2 and pATP423-MAE1, for activating the cytosolic or mitochondrial transhydrogenase-like shunt, respectively. The transformants were inoculated at an OD600 of 2 and grown in SD selectable medium containing 12 mg/L isoleucine. The cell growth was determined by measuring OD600 using a spectrophotometer. The concentrations of isobutanol, ethanol, and the total of 2-methyl-1-butanol and 3-methyl-1-butanol, in the media were determined using GC-MS. The concentrations of glucose and glycerol in the media were determined using HPLC. Each data point represents the mean (SD) values obtained from 3 replicate fermentations.