scholarly journals Electrode Colonization by the Feammox Bacterium Acidimicrobiaceae sp. Strain A6

2018 ◽  
Vol 84 (24) ◽  
Author(s):  
Melany Ruiz-Urigüen ◽  
Weitao Shuai ◽  
Peter R. Jaffé
Keyword(s):  
Iron Reduction ◽  
Electrical Current ◽  
Ammonium Oxidation ◽  
Riparian Wetland ◽  
Microbial Electrolysis Cells ◽  
Electrogenic Bacteria ◽  
Potential Electrode ◽  
Electrolysis Cells ◽  
Current Production ◽  
Reducing Bacteria

ABSTRACT Acidimicrobiaceae sp. strain A6 (A6), from the Actinobacteria phylum, was recently identified as a microorganism that can carry out anaerobic ammonium (NH4+) oxidation coupled to iron reduction, a process also known as Feammox. Being an iron-reducing bacterium, A6 was studied as a potential electrode-reducing bacterium that may transfer electrons extracellularly onto electrodes while gaining energy from NH4+ oxidation. Actinobacteria species have been overlooked as electrogenic bacteria, and the importance of lithoautotrophic iron reducers as electrode-reducing bacteria at anodes has not been addressed. By installing electrodes in the soil of a forested riparian wetland where A6 thrives, in soil columns in the laboratory, and in A6-bioaugmented constructed wetland (CW) mesocosms and by operating microbial electrolysis cells (MECs) with pure A6 culture, the characteristics and performances of this organism as an electrode-reducing bacterium candidate were investigated. In this study, we show that Acidimicrobiaceae sp. strain A6, a lithoautotrophic bacterium, is capable of colonizing electrodes under controlled conditions. In addition, A6 appears to be an electrode-reducing bacterium, since current production was boosted shortly after the CWs were seeded with enrichment A6 culture and current production was detected in MECs operated with pure A6, with the anode as the sole electron acceptor and NH4+ as the sole electron donor. IMPORTANCE Most studies on electrogenic microorganisms have focused on the most abundant heterotrophs, while other microorganisms also commonly present in electrode microbial communities, such as Actinobacteria strains, have been overlooked. The novel Acidimicrobiaceae sp. strain A6 (Actinobacteria) is an iron-reducing bacterium that can colonize the surface of anodes in sediments and is linked to electrical current production, making it an electrode-reducing bacterium. Furthermore, A6 can carry out anaerobic ammonium oxidation coupled to iron reduction. Therefore, findings from this study open the possibility of using electrodes instead of iron as electron acceptors, as a means to promote A6 to treat NH4+-containing wastewater more efficiently. Altogether, this study expands our knowledge of electrogenic bacteria and opens the possibility of developing Feammox-based technologies coupled to bioelectric systems for the treatment of NH4+ and other contaminants in anoxic systems.

scholarly journals Feammox Acidimicrobiaceae bacterium A6, a lithoautotrophic electrode-colonizing bacterium

2018 ◽  
Author(s):  
Melany Ruiz-Urigüen ◽  
Weitao Shuai ◽  
Peter R. Jaffé
Keyword(s):  
Iron Reduction ◽  
Electrical Current ◽  
Anaerobic Ammonium Oxidation ◽  
The Novel ◽  
Ammonium Oxidation ◽  
Riparian Wetland ◽  
Electrogenic Bacteria ◽  
Potential Electrode ◽  
Current Production ◽  
Reducing Bacteria

ABSTRACTAn Acidimicrobiaceae bacterium A6 (A6), from the Acitnobacteria phylum was recently identified as a microorganism that can carry out anaerobic ammonium oxidation coupled to iron reduction, a process also known as Feammox. Being an iron-reducing bacterium, A6 was studied as a potential electrode-reducing bacterium that may transfer electrons extracellularly onto electrodes while gaining energy from ammonium oxidation. Actinobacteria species have been overlooked as electrogenic bacteria, and the importance of lithoautotrophic iron-reducers as electrode-reducing bacteria at anodes has not been addressed. By installing electrodes in soil of a forested riparian wetland where A6 thrives, as well as in A6 bioaugmented constructed wetland (CW) mesocosms, characteristics and performances of this organism as an electrode-reducing bacterium candidate were investigated. In this study, we show that Acidimicrobiaceae bacterium A6 is a lithoautotrophic bacterium, capable of colonizing electrodes in the field as well as in CW mesocosoms, and that it appears to be an electrode-reducing bacterium since there was a boost in current production shortly after the CWs were seeded with Acidimicrobiaceae bacterium A6.IMPORTANCEMost studies on electrogenic microorganisms have focused on the most abundant heterotrophs, while other microorganisms also commonly present in electrode microbial communities such as Actinobacteria have been overlooked. The novel Acidimicrobiaceae bacterium A6 (Actinobacteria) is an iron-reducing bacterium that can colonize the surface of anodes and is linked to electrical current production, making it an electrode-reducing candidate. Furthermore, A6 can carry out anaerobic ammonium oxidation coupled to iron reduction, therefore, findings from this study open up the possibility of using electrodes instead of iron as electron acceptors as a mean to promote A6 to treat ammonium containing wastewater more efficiently. Altogether, this study expands our knowledge on electrogenic bacteria and opens up the possibility to develop Feammox based technologies coupled to bioelectric systems for the treatment NH4+ and other contaminants in anoxic systems.

scholarly journals Specific enrichment of hyperthermophilic electroactive Archaea from deep-sea hydrothermal vent on electrically conductive support

2018 ◽  
Author(s):  
Guillaume Pillot ◽  
Eléonore Frouin ◽  
Emilie Pasero ◽  
Anne Godfroy ◽  
Yannick Combet-Blanc ◽  
...  
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
Black Smoker ◽  
Electrically Conductive ◽  
Microbial Electrolysis Cells ◽  
Electrolysis Cells ◽  
Direct Inoculation ◽  
Current Production ◽  
Taxonomic Affiliation ◽  
A Current

AbstractWhile more and more investigations are done to isolate hyperthermophilic exoelectrogenic communities from environments, none have been performed yet on deep-sea hydrothermal vent. Samples of black smoker chimney from Rainbow site on the Atlantic mid-oceanic ridge have been harvested for enriching exoelectrogens in microbial electrolysis cells under hyperthermophilic (80°C) condition. Two enrichments have been performed: one from direct inoculation of crushed chimney and the other one from inoculation of a pre-cultivation on iron (III) oxide. In both experiments, a current production was observed from 2.4 A/m2 to 5.8 A/m2 with a set anode potential of +0.05 vs SHE. Taxonomic affiliation of the exoelectrogen communities obtained exhibited a specific enrichment of Archaea from Thermococcales and Archeoglobales orders on the electrode, even when both inocula were dominated by Bacteria.

scholarly journals Characterization of incubation experiments and development of an enrichment culture capable of ammonium oxidation under iron-reducing conditions

2015 ◽  
Vol 12 (3) ◽  
pp. 769-779 ◽  
Author(s):  
S. Huang ◽  
P. R. Jaffé
Keyword(s):  
Iron Reduction ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Enrichment Culture ◽  
Nitrogen Loss ◽  
Pcr Analysis ◽  
Rrna Gene ◽  
Ammonium Oxidation ◽  
Soil Slurry ◽  
Riparian Wetland ◽  
Incubation Experiments

Abstract. Incubation experiments were conducted using soil samples from a forested riparian wetland where we have previously observed anaerobic ammonium oxidation coupled to iron reduction. Production of both nitrite and ferrous iron was measured repeatedly during incubations when the soil slurry was supplied with either ferrihydrite or goethite and ammonium chloride. Significant changes in the microbial community were observed after 180 days of incubation as well as in a continuous flow membrane reactor, using 16S rRNA gene PCR-denaturing gradient gel electrophoresis, 454 pyrosequencing, and real-time quantitative PCR analysis. We be Acidimicrobiaceae bacterium A6), belonging to the Acidimicrobiaceae family, whose closest cultivated relative is Ferrimicrobium acidiphilum (with 92% identity) and Acidimicrobium ferrooxidans (with 90% identity), might play a key role in this anaerobic biological process that uses ferric iron as an electron acceptor while oxidizing ammonium to nitrite. After ammonium was oxidized to nitrite, nitrogen loss proceeded via denitrification and/or anammox.

scholarly journals Characterization of incubation experiments and development of an enrichment culture capable of ammonium oxidation under iron reducing conditions

2014 ◽  
Vol 11 (8) ◽  
pp. 12295-12321 ◽  
Author(s):  
S. Huang ◽  
P. R. Jaffé
Keyword(s):  
Iron Reduction ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Enrichment Culture ◽  
Nitrogen Loss ◽  
Pcr Analysis ◽  
Rrna Gene ◽  
Ammonium Oxidation ◽  
Soil Slurry ◽  
Riparian Wetland ◽  
Incubation Experiments

Abstract. Incubation experiments were conducted using soil samples from a forested riparian wetland where we have previously observed anaerobic ammonium oxidation coupled to iron reduction. Production of both nitrite and ferrous iron were measured repeatedly during incubations when the soil slurry was supplied with either ferrihydrite or goethite and ammonium chloride. Significant changes in the microbial community were observed after 180 days of incubation as well as in a continuous flow membrane reactor, using 16S rRNA gene PCR-denaturing gradient gel electrophoresis, 454-pyrosequencing, and real-time quantitative PCR analysis. We believe that one of the dominant microbial species in our system (an uncultured Acidimicrobiaceae bacterium A6), belonging to the Acidimicrobiaceae family, whose closest cultivated relative is Ferrimicrobium acidiphilum (with 92% identity) and Acidimicrobium ferrooxidans (with 90% identity), might play a key role in this anaerobic biological process that uses ferric iron as an electron acceptor while oxidizing ammonium to nitrite. After ammonium was oxidized to nitrite, nitrogen loss proceeded via denitrification and/or anammox.

scholarly journals Effects of Soil pH on Gaseous Nitrogen Loss Pathway via Feammox Process

2021 ◽  
Vol 13 (18) ◽  
pp. 10393
Author(s):  
Ding Ma ◽  
Jin Wang ◽  
Jun Xue ◽  
Zhengbo Yue ◽  
Shaofeng Xia ◽  
...  
Keyword(s):  
Soil Ph ◽  
Soil Acidification ◽  
Iron Reduction ◽  
Nitrogen Loss ◽  
Natural Environments ◽  
Ammonium Oxidation ◽  
N Loss ◽  
Molecular Biotechnology ◽  
Reducing Bacteria ◽  
Gaseous N Loss

The application of N fertilizer is one of the most critical soil acidification factors in China, and soil acidification significantly alters biogeochemical processes such as N loss. Anaerobic ammonium oxidation coupled with iron reduction (Feammox) is an important biological process for N loss in natural environments, with the end-products of N2, NO2− and NO3−. However, the response of Feammox pathways to soil pH fluctuation has not been thoroughly studied. In the current study, Feammox pathways and microbial communities were explored through a slurry culture experiment with an artificially adjusted pH combined with a 15N isotope tracing technique and molecular biotechnology. Results showed significant differences in the gaseous N loss through Feammox (0.42–0.97 mg N kg−1 d−1) under different pH conditions. The gaseous N loss pathways were significantly affected by the pH, and Feammox to N2 was the predominant pathway in low-pH incubations. The proportion of N loss caused by Feammox coupled with denitrification increased as the soil pH increased. The gaseous N loss through Feammox increased by 43.9% when the soil pH decreased from 6.5 to 5.0. Fe-reducing bacteria, such as Ochrobactrum, Sphingomonas, and Clostridium increased significantly in lower pH incubations. Overall, this study demonstrated the effects of soil pH on Feammox pathways and extended the understanding of the N biogeochemical cycle in acidic soil.

scholarly journals Sustainable Syntheses and Sources of Nanomaterials for Microbial Fuel/Electrolysis Cell Applications: An Overview of Recent Progress

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1221
Author(s):  
Domenico Frattini ◽  
Gopalu Karunakaran ◽  
Eun-Bum Cho ◽  
Yongchai Kwon
Keyword(s):  
Microbial Fuel Cells ◽  
Noble Metals ◽  
Raw Materials ◽  
Nanoparticle Synthesis ◽  
Economic Feasibility ◽  
Electrolysis Cell ◽  
Microbial Electrolysis Cells ◽  
Electrolysis Cells ◽  
Bioenergy Generation ◽  
Valuable Compounds

The use of microbial fuel cells (MFCs) is quickly spreading in the fields of bioenergy generation and wastewater treatment, as well as in the biosynthesis of valuable compounds for microbial electrolysis cells (MECs). MFCs and MECs have not been able to penetrate the market as economic feasibility is lost when their performances are boosted by nanomaterials. The nanoparticles used to realize or decorate the components (electrodes or the membrane) have expensive processing, purification, and raw resource costs. In recent decades, many studies have approached the problem of finding green synthesis routes and cheap sources for the most common nanoparticles employed in MFCs and MECs. These nanoparticles are essentially made of carbon, noble metals, and non-noble metals, together with a few other few doping elements. In this review, the most recent findings regarding the sustainable preparation of nanoparticles, in terms of syntheses and sources, are collected, commented, and proposed for applications in MFC and MEC devices. The use of naturally occurring, recycled, and alternative raw materials for nanoparticle synthesis is showcased in detail here. Several examples of how these naturally derived or sustainable nanoparticles have been employed in microbial devices are also examined. The results demonstrate that this approach is valuable and could represent a solid alternative to the expensive use of commercial nanoparticles.

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