Abstract
The low solubility of CO2 in water leads to massive CO2 emission and extremely low CO2 utilization in succinic acid (SA) biosynthesis. To enhance microbial CO2 utilization, micro-nano bubbles (MNBs) were induced in SA biosynthesis by E. coli Suc260 in this study. The results showed that MNB aeration decreased CO2 emissions and increased CO2 solubility in the medium significantly. The CO2 utilization of MNB aeration was 129.69% higher than that of bubble aeration in atmospheric fermentation. However, MNBs showed a significant inhibitory effect on bacterial growth in the pressurized environment, although a two-stage aerobic–anaerobic fermentation strategy weakened the inhibition. The biofilm-enhanced strain E. coli Suc260-CsgA showed a strong tolerance to MNBs. In pressurized fermentation with MNB aeration, the actual CO2 utilization of E. coli Suc260-CsgA was 30.63% at 0.18 MPa, which was a 6.49-times improvement. The CO2 requirement for SA synthesis decreased by 83.4%, and the fugitive emission of CO2 was successfully controlled. The activities of key enzymes within the SA synthesis pathway were also maintained or enhanced in the fermentation process with MNB aeration. These results indicated that the biofilm-enhanced strain and CO2-MNBs could improve carbon fixation efficiency in microbial carbon sequestration.
Published Version
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