Resistance assessment of microbial electrosynthesis for biochemical production to changes in delivery methods and CO flow rates.

Microbial electrosynthesis (MES) for CO valorization could be influenced by fluctuations in CO mass transfer and flow rates. In this study, we developed an efficient method for CO delivery to cathodic biofilm by directly sparging CO 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 CO flow rates varying from 0.3 ml/min to 10 ml/min. The biochemical production exhibited an increasing trend with CO flow rates, achieving higher acetate (47.0 ± 18.4 mmol/m/day) and methane (240.0 ± 32.2 mmol/m/day) generation at 10 ml/min with over 90% coulombic efficiency. The biofilm and suspended biomass, however, showed high resistance to CO flow fluctuations with Methanobacterium and Acetobacterium accounting for 80% of the total microbial community, which suggests the robustness of MES for onsite carbon conversion.