Fig. 1.

Retrobiosynthetic based design of the de novo IPA pathway for the generation of isoprenoid precursors from common C₂ and C₃ central carbon metabolites. Claisen, aldol, or acyloin condensation reactions combined with additional biochemical reactions could support the generation of IPAs from various central carbon metabolites (upper IPA pathway, green shading). These IPAs (green box) serve as the key intermediates linking the upper pathway to the lower IPA pathway (orange shading) in which diphosphorylation generates isoprenoid precursors from IPAs. Examples of individual pathways identified through this approach are shown in the SI Appendix, Figs. S10–S12. Representative isoprenoid products demonstrated in this study and enzymes utilized for their production are shown (geraniol, limonene, farsnesol, diaponeurosporene, and lycopene).