Figure 4

Biphasic xylitol and glycerol production. Panels A and B show glycerol formation in dependence of xylitol formation and xylose utilization, respectively. Corresponding ethanol formation is shown in Panel C. Panels A-C: BP10001 (full triangles), IBB10A02 (full circles), and IBB10B05 (empty circles). Panels D-I show glycerol (full circles) and CO₂ (empty circles) formation in dependence of formed xylitol and added bicarbonate (initial concentrations of CO₂ (aqueous): 0 (Panels D and G); 10 mM (Panel, E); 25 mM (Panels F and H) and fermentation form (Panels D-H, sealed flasks; Panel I, bioreactor). A pK of 6.5 was assumed for the relationship CO₂ + H₂O = H₃O⁺ + HCO₃ ^-. Experimental data obtained for IBB10A02 and IBB10B05 are shown in Panels D-F, I and Panels G, H respectively. Dashed lines indicate saturating concentrations of CO₂. The dotted line in Panel I depicts point of phase transition at 1.7 g/L CO₂.