流动电极微生物电合成提高产物生成速率及降低能量消耗

Flow-Electrode Microbial Electrosynthesis for Increasing Production Rates and Lowering Energy Consumption

微生物电合成(microbial electrosynthesis,MES)利用可再生电力驱动微生物固定CO_(2)合成化学品,在推进碳循环经济中具有一定潜力,受到广泛关注。但是,很少有研究通过高效反应器设计来促进产乙酸并降低能耗。本研究中,新型流动电极MES反应器的总产乙酸速率[(16±1)g·m^(-2)·d^(-1)]比无粉末活性炭(powder activated carbon,PAC)对照[(8±3)g·m^(-2)·d^(-1)]高两倍。流动电极MES反应器的库伦效率为43.5%±3.1%,能量消耗为(0.020±0.005)k Wh·g^(-1),产乙酸的能量效率为18.7%±1.3%。基于PAC的流动电极能够降低水跨膜通量、传质阻力,但是对装置电压、流变行为、乙酸吸附的影响较小。流动电极MES反应器中,能量代谢相关基因高表达,Acetobacterium的丰度增加。MES反应器中同时存在用于碳固定的还原性乙酰辅酶A途径(Wood–Ljungdahl pathway,WLP)与还原性三羧酸循环途径(reductive citric acid cycle,r TCA)。堆叠型流动电极MES中的乙酸浓度达7.0 g·L^(-1)。本研究提供一种构建可扩展MES反应器的新方法,促进CO_(2)利用以及产物生成。

The development of microbial electrosynthesis(MES)for renewable electricity-driven bioutilization of CO_(2)has recently attracted considerable interest due to its ability to synthesize chemicals with the transition towards a circular carbon economy.However,the increase of acetate production and the decrease of energy consumption of MES using an advanced reactor design have received less attention.In this study,the total acetate production rate using novel flow-electrode MES reactors((16±1)g·m^(-2)·d^(-1))was double that using reactors without powder activated carbon(PAC)amendment((8±3)g·m^(-2)·d^(-1)).The flow-electrode MES reactors had a Coulombic efficiency of 43.5%±3.1%,an energy consumption of(0.020±0.005)kW·h·g^(-1),and an energy efficiency of 18.7%±1.3%during acetate production.The flow-electrode with PAC amendment could decrease the net water flux and charge transfer resistance,while had little impact on the cell voltage,rheological behavior,and acetate adsorption.In the flowelectrode MES reactors,the expression of genes involving in energy production and conversion were increased,and the increase of acetate production was found correlated with the increased abundance of Acetobacterium.The Wood–Ljungdahl pathway(WLP)and reductive citric acid cycle(rTCA)were found to be the pathways responsible for carbon fixation.The concentrations of acetate in the stacked flowelectrode MES reached 7.0 gL1.This study presents a new approach for the construction of scalable MES reactors with high-performance chemical generation and CO_(2)utilization.