Fig. 4

Schematic representation of xylose utilization by C. sakazakii strain MOD1_Jor22. The proposed model for xylose utilization involves activation of the xylose regulon by the binding of D-xylose with XylR. It is thought that D-xylose enters the cell either through diffusion or transport via XylE or XylFGH. In addition, xylanase A (XynA) is secreted to the extracellular milieu through an unknown type 2 secretion component where it can digest xylan to β-xyloside which is then brought into the cell via a xyloside transporter (XynT, a putative β-xyloside transporter) where XynB (β-xylosidase) converts it to D-xylose. Though unconfirmed, α- xyloside is thought to be transported into the cell where XylS (α-xylosidase) converts to D- xylose. D-xylose then is converted to D-xylulose by XylA (xylose isomerase) and then converted to D-xylulose-5P by XylB (xylulokinase). This physiological pathway is identical to that of E. coli. Similar to that of E. coli, Cronobacter also have anaerobic metabolic pathway where D- xylose is converted to xylitol by oxidoreductase and then converted to D-xyloulose using NAD(P)-dependent alcohol dehydrogenase. D-xylulose-5P is then shunted into pentose- phosphate pathway