Resistance assessment of microbial electrosynthesis for biochemical production to changes in delivery methods and CO₂...

Microbial electrosynthesis (MES) for CO₂ valorization could be influenced by fluctuations in CO₂ mass transfer and flow rates. In this study, we developed an efficient method for CO₂ delivery to cathodic biofilm by directly sparging CO₂ through the pores of ceramic hollow fiber wrapped with Ni-foam/carbon nanotube electrode, and obtained 45% and 77% higher acetate and methane production, respectively. This was followed by the MES stability test in response to fluctuations in CO₂ flow rates varying from 0.3 ml/min to 10 ml/min. The biochemical production exhibited an increasing trend with CO₂ flow rates, achieving higher acetate (47.0 ± 18.4 mmol/m²/day) and methane (240.0 ± 32.2 mmol/m²/day) generation at 10 ml/min with over 90% coulombic efficiency. The biofilm and suspended biomass, however, showed high resistance to CO₂ flow fluctuations with Methanobacterium and Acetobacterium accounting for 80% of the total microbial community, which suggests the robustness of MES for onsite carbon conversion.