Novel Gas Diffusion Cloth Bioanodes for High-Performance Methane-Powered Microbial Fuel Cells

Abstract

Microbial fuel cells (MFCs) are a promising technology that converts chemical energy into electricity. However, up to now only few MFCs have been powered by gas fuels, such as methane, and their limited performance is still challenged by the low solubility and bioavailability of gases. Here, we developed a gas diffusion cloth (GDC) anode to significantly enhance the performance of methane-powered MFCs. The GDC anode was constructed by simply coating waterproof GORE-TEX cloth with conductive carbon cloth in one step. After biofilm enrichment, the GDC anodes obtained a methane-dependent current up to 1130.2 mA m −2 , which was 165.2 times higher than conventional carbon cloth (CC) anodes. Moreover, MFCs equipped with GDC anodes generated a maximum power density of 419.5 mW m −2 . Illumina high-throughput sequencing revealed that the GDC anode biofilm was dominated mainly by Geobacter, in contrast with the most abundant Methanobacterium in planktonic cells. It is hypothesized that Methanobacterium reversed the methanogenesis process by transferring electrons to the anodes, and Geobacter generated electricity via the intermediates (e.g., acetate) of anaerobic methane oxidation. Overall, this work provides an effective route in preparing facile and cost-effective anodes for high-performance methane MFCs.

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

“…Another optimization aspect is to further amplify the surface area of HFMs. Compared to the strategy of using GDE to increase CH 4 bioavailability [19], application of HFMs features the availability of higher membrane pack intensity for the higher surface to volume ratio, which could potentially enable incredible CH 4 diffusion and biomass incorporation as biofilm on HFMs.…”

“…To date, multiple strategies have been reported to effectively enhance performance of CH 4 -powered BESs. These strategies, including genetic manipulation to increase methyl-coenzyme M reductase (MCR) expression for faster CH 4 activation [ 13 ], as well as system optimization of configurating gas-diffusion electrode (GDE) to increase CH 4 bioavailability [ 19 ], have been demonstrated to enhance performance by orders of magnitude in comparison to their counterparts without any manipulation on biocatalysts or BES configuration (Additional file 1 : Table S2). The engineering approach presented in this study also shows impressive performance enhancement over these unmanipulated systems, although the current density achieved here is still inferior to some manipulated CH 4 -powered BESs reported to date (Additional file 1 : Table S2).…”

“…Specifically, CH 4 activation is all proposed to be activated by reverse methanogenesis via MCR in different methanotrophic consortia, while EET strategy varied depending on the MCR hosts (Additional file 1 : Table S2). An intermediate-dependent EET mechanism has been proposed in different methanotrophic consortia [ 13 , 19 ], within which CH 4 activator interact with other electroactive bacteria (i.e. Geobacter ) by diffusible intermediates, and final electron exchange with electrode are performed by the strong electricigen of Geobacter rather than CH 4 activators themselves.…”

“…While the implications of direct electricity production from CH 4 oxidation in BESs at ambient temperature is feasible, the technology is far from large-scale implementations due to the low current densities currently achievable [19], which are normally orders of magnitude lower than typically achieved by their bacterial electroactive counter parts, e.g., Geobacter [20]. The typically low rates of AOM catalysed by ANME and coupled with electrode reduction in BESs are probably the result of two rate-limiting processes, including (1) poor mass transfer rate and solubility of CH 4 in the cultivation media, which limits microbial accessibility to CH 4 ; (2) electron transfer from the microbial cells to the final external electron acceptor (i.e.…”

A Structured Approach for the Mitigation of Natural Methane Emissions—Lessons Learned from Anthropogenic Emissions

“…Captured methane could be concentrated and used as a substitute for natural gas or converted to chemicals for further valorization. Possible methods could be methane air capturing [155], similar to direct air capture for CO 2 , or the use of microbial fuel cells [156][157][158]. However, air capturing of low methane concentrations remains technologically challenging and no large-scale technology for the removal of non-point source emissions exists yet (Problem (9)).…”