Evaluating CO₂ fixation and sustainability in an integrated ethanol–succinic acid biorefinery

This study assesses the maximum theoretical CO₂ fixation, products (ethanol and succinic acid) yields, and carbon recovery rate in an integrated ethanol–succinic acid biorefinery. A global mass balance was conducted, considering sugarcane juice fractionation for succinic acid production and the stoichiometric reaction efficiencies of succinic acid and ethanol fermentation. Results showed that the biorefinery can consume up to 17.2 t.hr^-1 of CO₂, produce 92.4 t.hr^-1 of succinic acid, and achieve a carbon recovery of 94%. Sensitivity analysis showed that reducing the juice fraction for ethanol production and enhancing glucose conversion efficiency in succinic acid fermentation improve CO₂ fixation but affects ethanol yields. These findings highlight the potential of integrated biorefineries to reduce emissions while optimizing product yields and economic viability.