Fig. 4

Xylose utilization pathway enhanced for lipid production. a Schematic representation of the pathway leading to the consumption of xylose. XR xylose reductase; XDH xylitol dehydrogenase; and XK xylulose kinase represent the xylose consumption pathway (in red). XPKA phosphoketolase, ACK acetate kinase, and ACS2 acetyl-CoA synthase represent the XA pathway (in brown), while XPKA phosphoketolase and PTA phosphotransacetylase are the XP pathway (in blue). Dashed lines represent multiple metabolic steps. The bar graphs represent the lipid production (g/L) in the modified strains incorporating the XP or XA pathways compared to their parental strains, ylXYL+ (b) and ylXYL+Obese (c), when they were grown on xylose as a sole carbon source. The values represent the average values and the standard deviation of at least two replicates. The fold increase in relation with the parental strain is indicated on the top of each bar