Advanced bioproduct synthesis via reductive metabolism requires coordinating carbons, ATP and reducing agents, which are generated with varying efficiencies depending on metabolic pathways. Substrate mixtures with direct access to multiple pathways may optimally satisfy these biosynthetic requirements. However, native regulation favouring preferential use precludes cells from co-metabolizing multiple substrates. Here we explore mixed substrate metabolism and tailor pathway usage to synergistically stimulate carbon reduction. By controlled cofeeding of superior ATP and NADPH generators as ‘dopant’ substrates to cells primarily using inferior substrates, we circumvent catabolite repression and drive synergy in two divergent organisms. Glucose doping in Moorella thermoacetica stimulates CO2 reduction (2.3 g gCDW−1 h−1) into acetate by augmenting ATP synthesis via pyruvate kinase. Gluconate doping in Yarrowia lipolytica accelerates acetate-driven lipogenesis (0.046 g gCDW−1 h−1) by obligatory NADPH synthesis through the pentose cycle. Together, synergistic cofeeding produces CO2-derived lipids with 38% energy yield and demonstrates the potential to convert CO2 into advanced bioproducts. This work advances the systems-level control of metabolic networks and CO2 use, the most pressing and difficult reduction challenge.
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The data that support the findings of this study are available in the Supplementary Files and from the corresponding author upon request.
The authors declare no competing interests.
Peer review information: Primary Handling Editor: Ana Mateus.
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The authors would like to thank C. Lewis and E. Freinkman for their help with the LC–MS. This research was supported by the U.S. Department of Energy grant nos. DE-AR0000433, DE-SC0008744 and DE-SC0012377, as well as a Mobility Plus Fellowship no. 1284/MOB/IV/2015/0.