Electrochemically active bacteria 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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Advances in electrochemically active bacteria: Physiology and ecology

Handbook of Online and Near-real-time Methods in Microbiology ◽

10.1201/9781315153568-3 ◽

2017 ◽

pp. 42-76

Author(s):

A.C. Marques ◽

L. Santos ◽

J.M. Dantas ◽

A. Gonçalves ◽

S. Casaleiro ◽

...

Keyword(s):

Electrochemically Active ◽

Electrochemically Active Bacteria ◽

Active Bacteria

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Selective Enrichment of Electrochemically Active Bacteria in Microbial Fuel Cell By Pre-treatment of Mixed Anaerobic Sludge to Be Used as Inoculum

Springer Proceedings in Energy - Proceedings of the First International Conference on Recent Advances in Bioenergy Research ◽

10.1007/978-81-322-2773-1_23 ◽

2016 ◽

pp. 305-317

Author(s):

B. R. Tiwari ◽

M. M. Ghangrekar

Keyword(s):

Fuel Cell ◽

Microbial Fuel Cell ◽

Anaerobic Sludge ◽

Selective Enrichment ◽

Electrochemically Active ◽

Electrochemically Active Bacteria ◽

Active Bacteria ◽

Pre Treatment

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A Thin Layer of Activated Carbon Deposited on Polyurethane Cube Leads to New Conductive Bioanode for (Plant) Microbial Fuel Cell

Energies ◽

10.3390/en13030574 ◽

2020 ◽

Vol 13 (3) ◽

pp. 574

Author(s):

Emilius Sudirjo ◽

Paola Y. Constantino Diaz ◽

Matteo Cociancich ◽

Rens Lisman ◽

Christian Snik ◽

...

Keyword(s):

Fuel Cells ◽

Activated Carbon ◽

Field Test ◽

Microbial Fuel Cells ◽

Large Scale ◽

Electrode Materials ◽

Low Cost ◽

Three Dimensional ◽

Polyurethane Foams ◽

Electrochemically Active

Large-scale implementation of (plant) microbial fuel cells is greatly limited by high electrode costs. In this work, the potential of exploiting electrochemically active self-assembled biofilms in fabricating three-dimensional bioelectrodes for (plant) microbial fuel cells with minimum use of electrode materials was studied. Three-dimensional robust bioanodes were successfully developed with inexpensive polyurethane foams (PU) and activated carbon (AC). The PU/AC electrode bases were fabricated via a water-based sorption of AC particles on the surface of the PU cubes. The electrical current was enhanced by growth of bacteria on the PU/AC bioanode while sole current collectors produced minor current. Growth and electrochemical activity of the biofilm were shown with SEM imaging and DNA sequencing of the microbial community. The electric conductivity of the PU/AC electrode enhanced over time during bioanode development. The maximum current and power density of an acetate fed MFC reached 3 mA·m−2 projected surface area of anode compartment and 22 mW·m−3 anode compartment. The field test of the Plant-MFC reached a maximum performance of 0.9 mW·m−2 plant growth area (PGA) at a current density of 5.6 mA·m−2 PGA. A paddy field test showed that the PU/AC electrode was suitable as an anode material in combination with a graphite felt cathode. Finally, this study offers insights on the role of electrochemically active biofilms as natural enhancers of the conductivity of electrodes and as transformers of inert low-cost electrode materials into living electron acceptors.

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