Fig. 5

Schematic overview of metabolic engineering strategies adopted for isobutanol (IB) and 3-methyl-1-butanol (3M1B) production and the corresponding engineered Synechocystis sp. PCC 6803 strains. A Simplified pathway for IB and 3M1B biosynthesis. Endogenous pathways are written in black; heterologous pathways are written in red; targeting pathway for metabolic engineering are written in blue. Multiple enzymatic reactions are represented as dashed lines. Abbreviations of enzymes: FBA, aldolase (encoded by fbaA); TK, transketolase (encoded by tktA); PCK, phosphoenolpyruvate carboxykinase (encoded by pckA); TPI, triosephosphate isomerase (encoded by tpiA); PK, pyruvate kinase (encoded by pyk1). Abbreviations of intermediates: RuBP, ribulose-1,5-bisphosphate; 3PGA, 3-phosphoglycerate; G3P, glyceraldehyde-3-phosphate; DHAP, dihydroxyacetone phosphate; FBP, fructose-1,6-bisphosphate; SBP, sedoheptulose-1,7-bisphosphate; F6P, fructose-6-phosphate; S7P, sedoheptulose-7-phosphate; E4P, erythrose- 4-phosphate; Xu5P, xylulose-5-phosphate; R5P, ribose-5-phosphate; Ru5P, ribulose-5-phosphate; PEP, phosphoenolpyruvate; OAA, oxaloacetate. B Schematic diagram of plasmids used to generate Synechocystis strains in Fig. 5C and Fig. 6A–J. P5 is a self-replicating plasmid; P6, and P14-P21 are integrative plasmids targeting various sites of Synechocystis chromosome. C Genetic background of the engineered Synechocystis strains