Figure 4. n-Butanol production in metabolically engineered strains by individually overexpressing an additional copy of involved genes in the synergistic pathway.

All recombinant strains were constructed in the LI strain. HOM3*: HOM3 mutant encoding HOM3^G1355A 27. LEU4s: truncated LEU4 that starts at +91 ATG³³. Fermentation was performed in anaerobic glass tubes in YPAD media with 20 g/L glucose under micro-anaerobic condition as previously described¹⁸. Error bars indicate standard deviations of three biological replicates. A student’s t-test was used for statistical analysis of the n-butanol production in triplicates. Solid pentagram (★) indicates a result that was significantly different compared to the LI strain (p < 0.05).