Fig. 1.

Rewiring yeast central carbon metabolism for efficient production of aromatic chemicals. Introduction of a phosphoketolase (EC 4.1.2.22)-based pathway (green) to divert the glycolytic flux toward the formation of E4P. This consisted of a phosphoketolase to irreversibly cleave F6P into E4P and AcP, and a phosphotransacetylase to convert AcP into acetyl-CoA. The shikimate and AAA biosynthesis pathway were systematically investigated to relieve bottlenecks for biosynthesis of l-Phe and l-Tyr, two substrates for p-HCA production. A phenylalanine ammonia lyase and a cinnamic acid hydroxylase (PAL branch, pink) and a tyrosine ammonia lyase (TAL branch, blue) were both employed for the biosynthesis of p-HCA production. Further optimization of carbon distribution between glycolysis and the AAA biosynthesis pathway was achieved by fine-tuning glycolytic flux at phosphofructokinase and pyruvate kinase (blue triangles), via a combinatory promoter screening approach (see the main text). Glc glucose, G6P glucose-6-phosphate, F6P fructose-6-phosphate, F1,6BP fructose 1,6-biphosphate, G3P glyceraldehyde 3-phosphate, PEP phosphoenolpyruvate, Pyr pyruvate, AcP acetyl-phosphate, Ac-CoA acetyl-CoA, TCA tricarboxylic acid cycle, Ru5P ribulose 5-phosphate, R5P ribose-5-phosphate, X5P xylulose-5-phosphate, S7P sedoheptulose 7-phosphate, E4P erythrose-4-phosphate, DAHP 3-deoxy-d-arabino-2-heptulosonic acid 7-phosphate, CHA chorismic acid, PPA prephenate, l-Phe l-phenylalanine, l-Tyr l-tyrosine, l-Trp l-tryptophan, p-HCA p-coumaric acid