Pathways for 1,2-PD and 1,3-PD formation from glycolytic DHAP. E. coli genes encoding methylglyoxal synthase (mgs) and glycerol dehydrogenase (gldA) were introduced into S. cerevisiae per Lee and DaSilva (196) to enhance 1,2-PD production. In attempts to produce 1,3-PD in S. cerevisiae, bacterial genes encoding glycerol dehydratase and 1,3-PD oxidoreductase were expressed (42, 212) (see “Propanediol” in text).