Fig. 7

Metabolic pathways for the production of 1,3-butanediol (1,3-BDO). Two metabolic pathways have been proposed to produce 1,3-BDO via acetyl-CoA. In route ① (illustrated by green colors), acetyl-CoA is converted into 1,3-BDO by acetyl-CoA acetyltransferase, acetoacetyl-CoA reductase, butyryl-CoA dehydrogenase, and alcohol dehydrogenase. In route ② (illustrated by orange colors), acetyl-CoA is converted into 1,3-BDO by acetyl-CoA dehydrogenase, aldolase, and alcohol dehydrogenase. ackA acetate kinase, adhE acetaldehyde/alcohol dehydrogenase, bld butyryl-CoA dehydrogenase, ldhA lactate dehydrogenase, pfl pyruvate formate lyase, phaA acetyl-CoA acetyltransferase, phaB acetoacetyl-CoA reductase, pta phosphate acetyltransferase, yqhD NAD(P)H-dependent alcohol dehydrogenases