Figure 5.

Comparisons of cellobiose fermentation using strain D452-2 with the original (P _PGK1 -driven cdt-1 and gh1-1a ) and optimized (P _TDH3 -driven cdt-1 and P _CCW12 -driven gh1-1a ) cellobiose-utilizing pathways and transcription factor (TF) mutants. (A) Cellobiose-consumption rates and ethanol productivities with strains expressing the original and optimized cellobiose-utilization pathways, and also either overexpressing SUT1 or harboring a hap4 deletion. For details of the strains, see Additional file 4: Table S1. (B) Fermentation times of the strains in (A). (C) Comparisons of cellobiose-consumption rates and ethanol productivities with WT D452-2 or D452-2 (hap4Δ) expressing the optimized cellobiose-utilization pathway, and additionally overexpressing SUT1 and/or DAL80. (D) Fermentation times of the strains in (C), defined as the time when ethanol reached its maximum titer. In all experiments in (A–D), an initial OD₆₀₀ of 20 was used. Data represent the mean and standard error of triplicate cultures on each source. Statistical analysis in (A) and (C) was performed using two-way ANOVA (with strains and fermentation rate including q_smax and P_EtOH as the factors) followed by Tukey’s multiple-comparison posttest (***P < 0.001). Statistical analysis in (B) and (D) was performed using one-way ANOVA followed by Tukey’s multiple-comparison posttest (***P < 0.001).