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

doi:10.1186/s13068-020-01808-7

Enhancing methane oxidation in a bioelectrochemical membrane reactor using a soluble electron mediator

Biotechnol Biofuels. 2020 Oct 16:13:173. doi: 10.1186/s13068-020-01808-7. eCollection 2020.

Authors

Xueqin Zhang¹, Hesamoddin Rabiee¹, Joshua Frank¹, Chen Cai¹, Terra Stark^{2

3}, Bernardino Virdis¹, Zhiguo Yuan¹, Shihu Hu¹

Affiliations

¹ Advanced Water Management Centre, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, 4072 Australia.
² Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, 4072 Australia.
³ Queensland Node of Metabolomics Australia, The University of Queensland, Brisbane, 4072 Australia.

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: The combined use of HFMs and the soluble mediator increased the performance of ANME-based bioelectrochemical methane oxidation, enabling the delivery of up to 196 mA m^-2, 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.

Keywords: ANME; Bioelectrochemical membrane reactor; Bioelectrochemical methane oxidation; Ferricyanide; Redox mediator.