Fig. 1
Isobutanol (IB) and 3-methyl-1-butanol (3M1B) biosynthesis pathway. Carbon dioxide is fixed by the Calvin–Benson–Bassham (CBB) cycle, and the fixed carbon flows into the 2-keto acid pathway for IB and 3M1B biosynthesis. Endogenous enzymes are written in black, while heterologous enzymes are written in red. Abbreviations of enzymes: Sll0065, small subunit of native acetolactate synthase (AlsS); Slr2088, large subunit of native AlsS; Sll1363, native acetohydroxy-acid isomeroreductase (IlvC); Slr0452, native dihydroxy-acid dehydratase (IlvD); LeuA, 2-isopropylmalate synthase; LeuCD, 3-isopropylmalate dehydratase; LeuB, 3-isopropylmalate dehydrogenase; KivdS286T, α-ketoisovalerate decarboxylase (Lactococcus lactis); Slr1192OP, codon-optimized native alcohol dehydrogenase. Dotted lines indicate multiple reactions