Bioconversion of xylose to ethylene glycol and glycolate using
engineered C. glutamicum. (A) Xylose
was converted to either ethylene glycol or glycolate via synthetic
metabolic pathways in C. glutamicum. The SL-1 strain (C. glutamicum ΔxylB [encoding xylulose kinase]) was used as the parental
strain for the bioconversion. To convert xylose to either ethylene
glycol or glycolate, five enzymatic steps (shown in colored arrows)
were used by expressing genes encoding xylose isomerase (xylA) from E. coli, d-tagatose
3-epimerase (dte) from P. cichorii, l-fuculokinase (fucK) from E. coli, l-fuculose phosphate aldolase (fucA) from E. coli, aldehyde
dehydrogenase (aldA) from E. coli, and aldehyde reductase (yqhD) from E. coli in SL-1. Red “X” represents
gene deletion in C. glutamicum. Abbreviations:
G6P, glucose 6-phosphate; DHAP, dihydroxyacetone phosphate; PP pathway,
pentose phosphate pathway; Xu5P, xylulose 5-phosphate; GAP, glyceraldehyde
3-phosphate; and AcCoA, acetyl-CoA.