Fig. 1

Strategy for promoting carbon flux through PP pathway to improve co-production of H₂ and ethanol. EMP pathway was down-regulated by pfkA deletion (red) and PP pathway was activated by overexpression of zwf and gnd (blue). Genes: pgi—phosphoglucose isomerase, pfk—phosphofructokinase, gapA—glyceraldehyde-3-phosphate dehydrogenase, pta—phosphotransacetylase, ackA—acetate kinase, adhE—alcohol dehydrogenase, zwf—glucose-6-phosphate dehydrogenase, gnd—6-phosphogluconate dehydrogenase, edd—6-phosphogluconate dehyratase, eda—Entner–Doudoroff aldolase, udhA—soluble transhydrogenase, pntAB—membrane-bound transhydrogenase. Metabolites: G6P—glucose-6-phosphate, F6P—fructose-6-phosphate, FBP—fructose-1,6-bisphosphate, DHAP—dihydroxyacetone phosphate, G3P—glyceraldehyde-3-phosphate, 1,3-PG—1,3-bisphosphoglycerate, PYR—pyruvate, FOR—formate, H₂—hydrogen, AcCoA—acetyl CoA, ACE—acetate, EtOH—ethanol, 6PG—6-phosphogluconate, RL5P—ribulose-5-phosphate, X5P—xylose-5-phosphate, E4P—erythrose-4-phosphate, KDPG—2-Keto-3-deoxy-6-phosphogluconate