Fig. 1

The (2R,3R)-2,3-butanediol biosynthesis pathway of C. glutamicum. Genes manipulated in this study are indicated in red. The bold arrows indicate metabolic fluxes increased by overexpression of the corresponding genes. The gray arrows indicate the reactions leading to a byproduct or presumably irrelevant reactions. Deleted genes are indicated with crosses. Downregulated genes are indicated with dashed arrows. GAP: glyceraldehyde-3-phosphate; DHAP: dihydroxyacetone phosphate; DHA: dihydroxyacetone; G3P: sn-glycerol 3-phosphate; PEP: phosphoenolpyruvate; OAA: oxaloacetate. Genes and their encoded enzymes: alsS, acetolactate synthase; alsD, acetolactate decarboxylase; ppc, phosphoenolpyruvate carboxylase; pyc, pyruvate carboxylase; icd, isocitrate dehydrogenase; gltA, citrate synthase. pta, phosphotransacetylase; ackA, acetate kinase; aceE, E1 component of the pyruvate dehydrogenase complex; nagD, putative phosphatase; butA, meso-2,3-butanediol dehydrogenase; bdhA, (2R,3R)-2,3-butanediol dehydrogenase; udhA, transhydrogenase; atplBEFHAGDC, atp operon structure, atpI, hypothetical protein; atpB, a subunit of H⁺-ATPase synthase; atpE, c subunit; atpF, b subunit; atpH, δ subunit; atpA, α subunit; atpG, γ subunit; atpD, β subunit; atpC, ε subunit