Engineering synergetic CO 2 -fixing pathways for malate production.

Increasing the microbial CO2 -fixing efficiency often requires supplying sufficient ATP and redirecting carbon flux for the production of metabolites. However, addressing these two issues concurrently remains a challenge. Here, we present a combinational strategy based on a synergetic CO2 -fixing pathway that combines an ATP-generating carboxylation reaction in the central metabolic pathway with the ATP-consuming RuBisCO shunt in the carbon fixation pathway. This strategy provides enough ATP to improve the efficiency of CO2 fixation and simultaneously rewires the CO2 -fixing pathway to the central metabolic pathway for the biosynthesis of chemicals. We demonstrate the application of this strategy by increasing the CO2 -fixing rate and malate production in the autotroph Synechococcus elongatus by 110% and to 260 μM respectively, as well as increasing these two factors in the heterotrophic CO2 -fixing Escherichia coli by 870% and to 387 mM respectively.