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.
Keywords: ATP balance; CO(2) fixation; Malate production; Pathway engineering.
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