De novo artificial synthesis of hexoses from carbon dioxide.

Developing artificial "CO2 -sugar" platforms is meaningful for addressing challenges posed by land scarcity and climate change to the supply of dietary sugar. However, upcycling CO2 into complex polyoxygenated carbohydrates involves several major challenges, including achieving enantioselective and thermodynamically driven transformation and expanding product repertoires while reducing energy consumption. We present a versatile chemoenzymatic roadmap based on aldol condensation, iso/epimerization, and dephosphorylation reactions for asymmetric CO2 and H2 assembly into sugars with perfect stereocontrol. In particular, we developed a minimum ATP consumption and the shortest pathway for bottom-up biosynthesis of the fundamental precursor, fructose-6-phosphate, which is valuable for synthesizing structure-diverse sugars and derivatives. Engineering bottleneck-associated enzyme catalysts aided in the thermodynamically driven synthesis of several energy-dense and functional hexoses, such as glucose and D-allulose, featuring higher titer (63 mmol L-1 ) and CO2 -product conversion rates (25 mmol C L-1 h-1 ) compared to established in vitro CO2 -fixing pathways. This chemical-biological platform demonstrated greater carbon conversion yield than the conventional "CO2 -bioresource-sugar" process and could be easily extended to precisely synthesize other high-order sugars from CO2 .