Fig. 2
From: Flux-sum analysis identifies metabolite targets for strain improvement
Mixed acid fermentation pathway of E. coli. The pathways illustrate that the formation of various organic acids and ethanol occurs in parallel, utilizing phosphoenolpyruvate as the common precursor. Blue colored reactions represent the biosynthesis of desired products, succinate and ethanol, whereas red color indicates the production of unwanted acetate. Abbreviation: ac, acetate; acald, acetaldehyde; accoa, acetyl-CoA; actp, acetylphosphate; etoh, ethanol; for, formate; lac, lactate; mal, malate; oaa, oxaloacetate; pep, phosphoenolpyruvate; pyr, pyruvate; ACALD, acetaldehyde dehydrogenase; ACK, acetate kinase; ALCD, alcohol dehydrogenase; FRD, fumarate reductase; FUM, fumarase; LDH, lactate dehydrogenase; MDH, malate dehydrogenase; PFL, pyruvate formate lyase; PPC, phosphoenolpyruvate carboxylase; PTA, phosphate acetyltransferase; PYK, pyruvate kinase