Herein, Zymochem, Inc., in partnership with the National Renewable Energy Laboratory (NREL), proposes to develop carbon- and energy-efficient biocatalysts capable of co-conversion of C1- and biomass-derived substrates to a high-volume platform fuel and chemical intermediate. We propose to demonstrate a carbon conserving decoupled growth & production (DGP) process to enable improved carbon efficiency during the growth phase (using phosphoketolase (PKT) technology developed by NREL), 100% carbon efficient production of bioproducts (using the PKT pathway and carbon conserving (C2) technology developed at ZymoChem) during production phase using a C1 feedstock and biomass-derived sugars. Successful completion of this project will demonstrate the integration of carbon conserving technologies developed by ZymoChem and NREL to enable co-conversion of biomass sugars and C1 feedstock to (1) improve carbon efficiencies beyond current theoretical maxima during growth phase of a bioprocess, (2) achieve 100% carbon efficiencies during the production phase of a bioprocess, and (3) development of an industrial microbe making > 40 gC product/L of 6HH at > 53 kJ product/L/h productivity. The resultant technology will achieve Program Objectives to accommodate biological reductant demand in real-time, enable stoichiometric sugar splitting chemistries, and generate fuel- and chemical intermediates at or above titers and production rates prescribed by a corresponding system-level and commercial scale techno-economic analysis (TEA).