Fixing carbon dioxide in situ during ethanol production by formate dehydrogenase

Concerns regarding the increasing carbon dioxide (CO2) concentration has aroused global interest in renewable fuels and conversion of CO2 into chemicals. This study provides a sustainable strategy for fixing CO(2)in situ during the production of ethanol in a single cell expressing formate dehydrogenase (FDH) without the addition of a cofactor. Glucose was converted to ethanol, with the main by-product CO2 fixed to formate, increasing the yield of ethanol and glucose fermentation efficiency in the recombinant Saccharomyces cerevisiae-fdh. Higher concentrations of glucose and amount of ScFDH1 yielded more formate, confirming the feasibility of CO2 fixation. Significantly, the glucose consumption rate and ethanol yield increased by 30% and 13% after the overexpression of ScFDH1, respectively. Finally, the increase in CO2 concentration with the addition of zeolite imidazole framework-8 (ZIF-8) further demonstrated the CO2 fixation in situ, increasing the production of formate 2.1 times. Due to ZIF-8, up to 60.67 mg L-1 formate was produced. Our findings establish a green, economical, and sustainable alternative for CO2 conversion in situ, contributing to the ethanol yield by ScFDH1 without extra energy input and cofactor supply. This synergistic strategy has significance for both the energy and environmental crises.