Fig. 4

Fermentation performance of strains with single and double mutations in LpXI integrated into the chromosome in glucose/xylose co-fermentation under micro-aerobic conditions. Batch fermentation examinations were performed under the same conditions as for Figs. 2 and 3. The fermentation properties of strains are shown for SS104 (LpXI-V162A, single mutation, from SS92), SS105 (LpXI-N303T, single mutation, from SS92) and SS120 (LpXI-T63I/V162A, combination of mutations from SS82 and SS92, respectively). The mutated LpXI expression cassettes were introduced into the AUR1 locus of the chromosome of the parental strain SS29 via homologous recombination. The dots and error bars in the panels represent the mean concentrations and standard deviations, respectively, of the following metabolites in biological triplicates: glucose (blue), xylose (red), xylitol (yellow green), glycerol (purple), acetate (light blue) and ethanol (orange). The details for the metabolite concentrations are shown in Additional file 10: Table S7