A scalable model of fluid flow, substrate removal and current production in microbial fuel cells

Microbial fuel cells (MFCs) can convert chemical energy to electricity using microbes as catalysts and a variety of organic wastewaters as substrates. However, electron loss occurs when fermentable substrates are used because fermentation bacteria and methanogens are involved in electron flow from the substrates to electricity. In this study, MFCs using glucose (G-MFC), propionate (P-MFC), butyrate (B-MFC), acetate (A-MFC), and a mix (M-MFC, glucose:propionate:butyrate:acetate = 1:1:1:1) were operated in batch mode. The metabolites and microbial communities were analyzed. The current was the largest electron sink in M-, G-, B-, and A-MFCs; the initial chemical oxygen demands (CODini) involved in current production were 60.1% for M-MFC, 52.7% for G-MFC, 56.1% for B-MFC, and 68.3% for A-MFC. Most of the glucose was converted to propionate (40.6% of CODini) and acetate (21.4% of CODini) through lactate (80.3% of CODini) and butyrate (6.1% of CODini). However, an unknown source (62.0% of CODini) and the current (34.5% of CODini) were the largest and second-largest electron sinks in P-MFC. Methane gas was only detected at levels of more than 10% in G- and M-MFCs, meaning that electrochemically active bacteria (EAB) could out-compete acetoclastic methanogens. The microbial communities were different for fermentable and non-fermentable substrate-fed MFCs. Probably, bacteria related to Lactococcus spp. found in G-MFCs with fermentable substrates would be involved in both fermentation and electricity generation. Acinetobacter-like species, and Rhodobacter-like species detected in all the MFCs would be involved in oxidation of organic compounds and electricity generation.

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Rumen Inoculum Enhances Cathode Performance in Single-Chamber Air-Cathode Microbial Fuel Cells

Materials ◽

10.3390/ma15010379 ◽

2022 ◽

Vol 15 (1) ◽

pp. 379

Author(s):

Ignacio T. Vargas ◽

Natalia Tapia ◽

John M. Regan

Keyword(s):

Fuel Cells ◽

Microbial Fuel Cells ◽

Rumen Fluid ◽

Oxygen Demand ◽

Air Cathode ◽

Single Chamber ◽

Higher Power ◽

Mixed Microbial Community ◽

Current Production ◽

Soluble Chemical Oxygen Demand

During the last decade, bioprospecting for electrochemically active bacteria has included the search for new sources of inoculum for microbial fuel cells (MFCs). However, concerning power and current production, a Geobacter-dominated mixed microbial community derived from a wastewater inoculum remains the standard. On the other hand, cathode performance is still one of the main limitations for MFCs, and the enrichment of a beneficial cathodic biofilm emerges as an alternative to increase its performance. Glucose-fed air-cathode reactors inoculated with a rumen-fluid enrichment and wastewater showed higher power densities and soluble chemical oxygen demand (sCOD) removal (Pmax = 824.5 mWm−2; ΔsCOD = 96.1%) than reactors inoculated only with wastewater (Pmax = 634.1 mWm−2; ΔsCOD = 91.7%). Identical anode but different cathode potentials suggest that differences in performance were due to the cathode. Pyrosequencing analysis showed no significant differences between the anodic community structures derived from both inocula but increased relative abundances of Azoarcus and Victivallis species in the cathodic rumen enrichment. Results suggest that this rarely used inoculum for single-chamber MFCs contributed to cathodic biofilm improvements with no anodic biofilm effects.

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In situ continuous current production from marine floating microbial fuel cells

Applied Energy ◽

10.1016/j.apenergy.2018.08.061 ◽

2018 ◽

Vol 230 ◽

pp. 78-85 ◽

Cited By ~ 7

Author(s):

Giulia Massaglia ◽

Valentina Margaria ◽

Adriano Sacco ◽

Tonia Tommasi ◽

Simona Pentassuglia ◽

...

Keyword(s):

Fuel Cells ◽

Microbial Fuel Cells ◽

Continuous Current ◽

Current Production

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Enhanced current production of the anode modified by microalgae derived nitrogen-rich biocarbon for microbial fuel cells

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2019.06.199 ◽

2020 ◽

Vol 45 (6) ◽

pp. 3833-3839 ◽

Cited By ~ 4

Author(s):

Linghan Lan ◽

Jun Li ◽

Qing Feng ◽

Liang Zhang ◽

Qian Fu ◽

...

Keyword(s):

Fuel Cells ◽

Microbial Fuel Cells ◽

Current Production

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Fungi-Based Microbial Fuel Cells

Energies ◽

10.3390/en11102827 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2827 ◽

Cited By ~ 19

Author(s):

Anna Sekrecka-Belniak ◽

Renata Toczyłowska-Mamińska

Keyword(s):

Electron Transfer ◽

Fuel Cells ◽

Microbial Fuel Cells ◽

State Of The Art ◽

Metabolic Processes ◽

Cathode Catalysts ◽

Current State ◽

Starting Point ◽

Potential Applicability ◽

Current Production

Fungi are among the microorganisms able to generate electricity as a result of their metabolic processes. Throughout the last several years, a large number of papers on various microorganisms for current production in microbial fuel cells (MFCs) have been published; however, fungi still lack sufficient evaluation in this regard. In this review, we focus on fungi, paying special attention to their potential applicability to MFCs. Fungi used as anodic or cathodic catalysts, in different reactor configurations, with or without the addition of an exogenous mediator, are described. Contrary to bacteria, in which the mechanism of electron transfer is pretty well known, the mechanism of electron transfer in fungi-based MFCs has not been studied intensively. Thus, here we describe the main findings, which can be used as the starting point for future investigations. We show that fungi have the potential to act as electrogens or cathode catalysts, but MFCs based on bacteria–fungus interactions are especially interesting. The review presents the current state-of-the-art in the field of MFC systems exploiting fungi.

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Coupled substrate removal and electricity generation in microbial fuel cells simultaneously treating sulfide and nitrate at various influent sulfide to nitrate ratios

Bioresource Technology ◽

10.1016/j.biortech.2020.123174 ◽

2020 ◽

Vol 306 ◽

pp. 123174

Author(s):

Jing Cai ◽

Mahmood Qaisar ◽

Yue Sun ◽

Kaiquan Wang ◽

Juqing Lou ◽

...

Keyword(s):

Fuel Cells ◽

Microbial Fuel Cells ◽

Electricity Generation ◽

Substrate Removal

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The effects of electrode spacing on the performance of microbial fuel cells under different substrate concentrations

Water Science & Technology ◽

10.2166/wst.2013.446 ◽

2013 ◽

Vol 68 (9) ◽

pp. 2028-2034 ◽

Cited By ~ 7

Author(s):

Chi-Yuan Lee ◽

Ya-Ni Huang

Keyword(s):

Fuel Cells ◽

Power Output ◽

Microbial Fuel Cells ◽

Electricity Generation ◽

Oxygen Demand ◽

Electrode Placement ◽

Electrode Spacing ◽

Organic Removal ◽

Half Saturation Constant ◽

Current Production

In this study, the electricity generation and organic removal in microbial fuel cells (MFCs) were examined for electrode spacing (ES) covering 5.8, 10.2, 15.1, and 19.5 cm, and for each ES the MFCs were discharged with a series of influent substrates (CODin). Results indicate that organic removal was related to CODin but not to ES. Best chemical oxygen demand (COD) removals of 64–71% could be achieved at CODin around 100 mg COD/L (0.11–0.14 kg COD/m3-day). Best power output 3.32 mW/m2 occurred at ES 5.8 cm and nominal CODin 300 mg COD/L. For every ES, the relationship of electricity generation to local substrate near anode (CODad) could be adequately modeled by Monod-type kinetics. The estimated kinetic constants involve maximum current production, Imax, 15.3–19.6 mA/m2; maximum attainable power output, Pp,max, 4.0–2.5 mW/m2; half-saturation constant of current, Ksi, 22–30 mg COD/L; and half-saturation constant of power, Ksp, 24–90 mg COD/L. This study reveals that the control over ES for improving electricity generation is dependent on the level of CODad, which profoundly affects the optimal design of electrode placement.

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