Dissolved CO₂ profile in bio-succinic acid production from sugars-rich industrial waste

The inorganic carbon source (CO₂) availability to the microorganisms has a key role in the succinic acid (SA) fermentation process. This study aims to investigate the behavior of the inorganic carbon source for SA production and underline the importance of CO₂ in the fermentation process. The effect of pressure was investigated for CO₂ availability and its overall impact on the fermentation process. Results obtained demonstrated a significant effect of pressure on yield, productivity and CO₂ fixation rate. Industrial waste, rich in maltose, glucose, and sucrose, was used as feedstock combined with a gas mixture of CH₄ and CO₂, which simulated biogas composition. A final titer for succinic acid of 25.5 ± 2.4 g/L was detected at a headspace gas pressure of 1.4 atm. The yield raised from 0.48 g/g sugars to 0.64 and 0.65 g/g sugars when 1.4 and 1.6 atm pressure was applied, respectively. Overall, this study represents one of the first attempts to explore CO₂ availability during succinic acid production, using biogas as a CO₂ source and sugars-rich industrial waste as feedstock.