Fig. 7.

Reduction of ethanol, glycerol and isobutyric acid biosyntheses increases isobutanol production. Fermentation experiments were performed aerobically at 30 °C in shake flasks in selective SCD medium without valine containing 40 g/L glucose. Pre-cultures carrying the episomal 2µ-plasmid IsoV100 were grown aerobically in fermentation medium, harvested at an OD₆₀₀ ≤ 3 and inoculated in fresh fermentation medium at a final OD₆₀₀ of 8. Fermentation experiments were performed at least in duplicate. Error bars indicate standard deviation for experiments performed twice and standard error for experiments performed at least three times, respectively. a Glucose consumption after successively blocking of competing isobutanol pathways by deletion of key enzymes of biosynthesis pathways: CEN.PK113-7D (wt); JWY04 (∆ilv2; Δbdh1; Δbdh2; Δleu4; Δleu9; Δecm31; Δilv1); JWY16 (∆ilv2; Δbdh1; Δbdh2; Δleu4; Δleu9; Δecm31; Δilv1; Δadh1); JWY17 (∆ilv2; Δbdh1; Δbdh2; Δleu4; Δleu9; Δecm31; Δilv1; Δadh1; Δgpd1); JWY18 (∆ilv2; Δbdh1; Δbdh2; Δleu4; Δleu9; Δecm31; Δilv1; Δadh1; Δgpd2); JWY19 (∆ilv2; Δbdh1; Δbdh2; Δleu4; Δleu9; Δecm31; Δilv1; Δadh1; Δgpd1; Δgpd2); JWY23 (∆ilv2; Δbdh1; Δbdh2; Δleu4; Δleu9; Δecm31; Δilv1; Δadh1; Δgpd1; Δgpd2; Δald6). b Isobutanol production. c Glycerol production. d Ethanol production