Figure 1.

D-Glucose and D-xylose consumption and xylitol and L-lactic acid production in buffered microaerobic cultivation. (A). Consumption of D-glucose [♦◊] and D-xylose [■□], and production of xylitol [▲Δ] and lactic acid [●○] by C. sonorensis C169 (2*ldhL, pdc1Δ, pdc2Δ) in CaCO₃-buffered YNB with 30 g l⁻¹ D-glucose and 30 g l⁻¹ D-xylose at 30°C, 100 rpm. Cultures were inoculated with cells which had been pre-cultured on D-xylose (closed symbols) or D-glucose (open symbols). (B). Xylose reductase (XR, NADPH-dependent), xylitol dehydrogenase (XDH) and xylulokinase (XK) activities assayed after 27 h of cultivation in CaCO₃-buffered YNB with 30 g l⁻¹ D-glucose and 30 g l⁻¹ D-xylose. Cultures were inoculated with D-xylose (black bars) or D-glucose (white bars) grown cells. Results are averages ± sem from duplicate flask cultivations. Where error bars are not visible they were smaller than the symbol. An asterisk indicates that the value is significantly different (p < 0.05) from that of the cultures inoculated with D-glucose-grown cells.