FIG 1.
Metabolic pathways for propionic acid, lactic acid, and acetic acid biosynthesis from glycerol in Propionibacterium. Engineered biosynthesis steps by the overexpression of the corresponding genes are indicated by color blocks. The arrows with dotted lines represent multiple reactions. Lactic acid and acetic acid are the main by-products in propionic acid production. EMP, Embden-Meyerhof-Parnas; DHA, dihydroxyacetone; DHAP, dihydroxyacetone phosphate; TCA, tricarboxylic acid; FP, flavoprotein; FPH3, flavoprotein-H3.