Fig. 3

Xylose fermentation in S. cerevisiae. The fungal pathway uses xylose reductase (XR) and xylitol dehydrogenase (XDH), whereas the bacterial pathway uses xylose isomerase (XI). Both pathways produce d-xylulose which is converted to d-xylulose-5P by endogenous xylulokinase (XK). d-Xylulose-5P then enters the pentose phosphate pathway (PPP), where it is further metabolized to form ethanol under appropriate conditions. Arrows indicate the direction of the chemical reactions (Moysés et al. 2016)