Fig. 3
Time-course of fermentation profiles of the parental (JHL61, a) and engineered (GAL_061, b) strains for 48 h. Implementation of the galactose utilization pathway enhanced n-butanol production dramatically. The left y-offset and right y-axis represent galactose and metabolite (n-butanol, ethanol, and butyrate) concentrations (g/L), respectively. The left y-axis represents OD600. The x-axis represents time in culture (h). The error bars indicate standard deviations of measurements from two independent cultures. Symbols: open circle OD600; open rectangle galactose; closed up triangle n-butanol; closed diamond ethanol; closed down triangle butyrate