Enhancing methane oxidation in a bioelectrochemical membrane reactor using a soluble electron mediator
Xueqin Zhang, Hesamoddin Rabiee, Joshua Frank, Chen Cai, Terra Stark, Bernardino Virdis, Zhiguo Yuan, Shihu Hu
Abstract
BACKGROUND: Bioelectrochemical methane oxidation catalysed by anaerobic methanotrophic archaea (ANME) is constrained by limited methane bioavailability as well as by slow kinetics of extracellular electron transfer (EET) of ANME. In this study, we tested a combination of two strategies to improve the performance of methane-driven bioelectrochemical systems that includes (1) the use of hollow fibre membranes (HFMs) for efficient methane delivery to the ANME organisms and (2) the amendment of ferricyanide, an effective soluble redox mediator, to the liquid medium to enable electrochemical bridging between the ANME organisms and the anode, as well as to promote EET kinetics of ANME. RESULTS: , thereby outperforming the control system by 244 times when HFMs were pressurized at 1.6 bar. CONCLUSIONS: Improving methane delivery and EET are critical to enhance the performance of bioelectrochemical methane oxidation. This work demonstrates that by process engineering optimization, energy recovery from methane through its direct oxidation at relevant rates is feasible.