Efficient Carbon Dioxide Utilization for Succinic Acid Production by Combination of Amine-Modified Cellulose Sponge, CO 2 Micronano Bubbles, and Biofilms

During succinic acid (SA) biosynthesis, increasing the utilization of CO 2 is beneficial for reducing greenhouse gas emissions and lowering production costs. In this study, amine-modified cellulose sponges (AMCS) were prepared, which could decrease more than 80% of CO 2 emissions in water by adsorption and chemical reaction. An external fibrous bed bioreactor was filled with AMCS, and the repeated-batch pressurized fermentation was supplied with CO 2 micronano bubbles (MNBs) without any carbonates or bicarbonates. In this process, Escherichia coli Suc260-CsgA could form stable biofilms on AMCS, which exhibited significantly enhanced resistance to free radicals. Compared with free-cell batch fermentation under atmospheric pressure, the average productivity of SA and yield were increased by 77.36 and 8.11%. The carbonic anhydrase activity of the biofilm was over 68% higher than that in free-cell fermentation mode, while the actual CO 2 utilization increased 2.88-fold. The results indicated that the microbial carbon sequestration was enhanced and the anabolic metabolism of SA was accelerated by the combination of the biofilm, AMCS, and MNBs.