• 2024

• 2023

• 2013

Power production from microbial reverse electrodialysis cell (MRC) electrodes is substantially improved compared to microbial fuel cells (MFCs) by using ammonium bicarbonate (AmB) solutions in multiple RED cell pair stacks and the cathode chamber. Reducing the number of RED membranes pairs while maintaining enhanced electrode performance could help to reduce capital costs. We show here that using only a single RED cell pair (CP), created by operating the cathode in concentrated AmB, dramatically increased power production normalized to cathode area from both acetate (Acetate: from 0.9 to 3.1 W/m(2)-cat) and wastewater (WW: 0.3 to 1.7 W/m(2)), by reducing solution and charge transfer resistances at the cathode. A second RED cell pair increased RED stack potential and reduced anode charge transfer resistance, further increasing power production (Acetate: 4.2 W/m(2); WW: 1.9 W/m(2)). By maintaining near optimal electrode power production with fewer membranes, power densities normalized to total membrane area for the 1-CP (Acetate: 3.1 W/m(2)-mem; WW: 1.7 W/m(2)) and 2-CP (Acetate: 1.3 W/m(2)-mem; WW: 0.6 W/m(2)) reactors were much higher than previous MRCs (0.3-0.5 W/m(2)-mem with acetate). While operating at peak power, the rate of wastewater COD removal, normalized to reactor volume, was 30-50 times higher in 1-CP and 2-CP MRCs than that in a single chamber MFC. These findings show that even a single cell pair AmB RED stack can significantly enhance electrical power production and wastewater treatment.

• 2015

• 2012

Reverse electrodialysis allows for the capture of energy from salinity gradients between salt and fresh waters, but potential applications are currently limited to coastal areas and the need for a large number of membrane pairs. Using salt solutions that could be continuously regenerated with waste heat (≥40°C) and conventional technologies would allow much wider applications of salinity-gradient power production. We used reverse electrodialysis ion-exchange membrane stacks in microbial reverse-electrodialysis cells to efficiently capture salinity-gradient energy from ammonium bicarbonate salt solutions. The maximum power density using acetate reached 5.6 watts per square meter of cathode surface area, which was five times that produced without the dialysis stack, and 3.0 ± 0.05 watts per square meter with domestic wastewater. Maximum energy recovery with acetate reached 30 ± 0.5%.

• 2024

• 2024

• 2017

• 2021

• 2022

Microbial fuel cell (MFC) is a green innovative technology that can be employed for nutrient removal/recovery as well as for energy production from wastewater. This paper summarizes the recent advances in the use of MFCs for nutrient removal/recovery. Different configurations of MFCs used for nutrient removal are first described. Different types of nutrient removal/recovery mechanisms such as precipitation, biological uptake by microalgae, nitrification, denitrification and ammonia stripping occurring in MFCs are discussed. Recovery of nutrients as struvite or cattiite by precipitation, as microalgal biomass and as ammonium salts are common. This review shows that while higher nutrient removal/recovery is possible with MFCs and their modifications compared to other techniques as indicated by many laboratory studies, field-scale studies and optimization of operational parameters are needed to develop efficient MFCs for nutrient removal and recovery and electricity generation from different types of wastewaters.

• 2019

• 2017

• 2021

.

• 2021

The transformation of a microbial fuel cell to a microbial nutrient recovery cell has gained attention worldwide since it offers a potential simultaneous solution to the challenges of nutrient and energy recovery from waste streams. Herein, we reported for the first time the use of chitosan beads as a novel eco-friendly anodic material to accommodate electrochemically active bacteria for the efficient recovery of nutrients and the production of energy from wastewater without any external supply of electricity. The developed chitosan bioanode was systematically researched and compared with an activated carbon anode for its potential in terms of nutrient removal and recovery, chemical oxygen demand removal, and energy production from municipal wastewater. The maximum power density estimated for the chitosan-based system (∼600 mW/m2) was found to be as efficient as the activated carbon-based system (∼650 mW/m2). Overall, this study demonstrates a facile/schematic self-driven route for the recovery and enrichment of nutrients (phosphorus recovery of ∼65% and ammonium recovery of ∼64%) from municipal wastewater along with stable voltage production during the whole procedure.

• 2018

• 2005

BACKGROUND: Microbial biofilms exist all over the natural world, a distribution that is paralleled by metal cations and oxyanions. Despite this reality, very few studies have examined how biofilms withstand exposure to these toxic compounds. This article describes a batch culture technique for biofilm and planktonic cell metal susceptibility testing using the MBEC assay. This device is compatible with standard 96-well microtiter plate technology. As part of this method, a two part, metal specific neutralization protocol is summarized. This procedure minimizes residual biological toxicity arising from the carry-over of metals from challenge to recovery media. Neutralization consists of treating cultures with a chemical compound known to react with or to chelate the metal. Treated cultures are plated onto rich agar to allow metal complexes to diffuse into the recovery medium while bacteria remain on top to recover. Two difficulties associated with metal susceptibility testing were the focus of two applications of this technique. First, assays were calibrated to allow comparisons of the susceptibility of different organisms to metals. Second, the effects of exposure time and growth medium composition on the susceptibility of E. coli JM109 biofilms to metals were investigated. RESULTS: This high-throughput method generated 96-statistically equivalent biofilms in a single device and thus allowed for comparative and combinatorial experiments of media, microbial strains, exposure times and metals. By adjusting growth conditions, it was possible to examine biofilms of different microorganisms that had similar cell densities. In one example, Pseudomonas aeruginosa ATCC 27853 was up to 80 times more resistant to heavy metalloid oxyanions than Escherichia coli TG1. Further, biofilms were up to 133 times more tolerant to tellurite (TeO3(2-)) than corresponding planktonic cultures. Regardless of the growth medium, the tolerance of biofilm and planktonic cell E. coli JM109 to metals was time-dependent. CONCLUSION: This method results in accurate, easily reproducible comparisons between the susceptibility of planktonic cells and biofilms to metals. Further, it was possible to make direct comparisons of the ability of different microbial strains to withstand metal toxicity. The data presented here also indicate that exposure time is an important variable in metal susceptibility testing of bacteria.

• 2002

• 2024

• 2014

• 1997

• 2024

• 2016

• 2020

• 2014

• 2021

Tuba électrochimique microbien pour la réduction des nitrates dans les zones humides La concentration excessive de nitrates dans les eaux est due à l'utilisation d'engrais azotés dans l'agriculture et peut avoir des conséquences environnementales négatives, telles que l'eutrophisation des eaux de surface, l'augmentation des émissions de N₂O (un gaz à effet de serre) ou la toxicité de l'eau pour la faune aquatique [1]. L'une des solutions proposées pour réduire la quantité de nitrates dans l'eau est la construction de zones humides - des systèmes d'ingénierie qui utilisent les processus naturels tels que la végétation, les sédiments et les bactéries des zones humides pour aider à traiter les eaux usées [2]. Cependant, cette approche peut ne pas être assez rapide, surtout dans les périodes où la concentration de nitrates est élevée et dans les zones humides de taille insuffisante. Cette thèse explore des stratégies pour accélérer la réduction des nitrates. La réaction de dénitrification nécessite un donneur d'électrons, qui peut être du carbone organique. Ces composés apparaissent davantage dans les sédiments, alors que le nitrate est présent dans l'eau. Nous avons donc émis l'hypothèse que l'augmentation de l'interface sédiment/eau faciliterait l'accès aux donneurs d'électrons et accélérerait la dénitrification, ce que nous avons évalué dans la première partie de ce travail. Une manière de relier les sources d’électron dans les sédiments aux ions nitrates était de mettre en œuvre un système bioélectrochimique. Le système exploré dans cette thèse est un tuba électrochimique microbien, qui consiste en une seule pièce d'électrode, immergée dans deux milieux différents, ici les sédiments et l’eau. Dans le sédiment, un biofilm anodique peut être développé sur l’électrode, qui oxyde la matière organique. Les électrons sont transportés vers la partie se trouvant dans l'eau, où un biofilm cathodique se développe et le processus de réduction se produit. Les accepteurs d'électrons peuvent être ici l'oxygène ou le nitrate. L'un des objectifs de ce travail est de créer les conditions dans lesquelles le tuba électrochimique avec partie biocathodique réduisant les nitrates est développée et de caractériser ses propriétés bioélectrochimiques, la communauté microbienne de son biofilm et l'efficacité de la réduction des nitrates. Le chapitre 1 présente une revue de la littérature sur les biocathodes pour réduction des nitrates. Le chapitre 2 décrit les matériaux et méthodes utilisés dans ce travail. Le chapitre 3 décrit la zone humide artificielle et étudie l'effet de l'augmentation de l'interface eau/sédiment sur la réduction des nitrates et explore à partir d’un modèle les conséquences de l’amélioration des performances en dénitrification dans la zone humide de Rampillon.Le chapitre 4 couvre les études préliminaires du tuba électrochimique: le choix des matériaux de l'électrode et la proportion entre la partie dans l'eau et dans les sédiments. De plus, le développement du système est confirmé par des analyses électrochimiques ainsi que par l'étude de la communauté microbienne. L'ajout de nitrate provoque alors l'augmentation du courant cathodique et le déplacement du potentiel. Les résultats obtenus en laboratoire ont été comparés aux résultats obtenus sur le terrain. Cette expérience a été suivie par la construction d'un autre tuba électrochimique avec une taille d'électrodes plus importante et une configuration optimisée (chapitre 5). Cette expérience conduit à une nette augmentation de la vitesse de réduction des nitrates en lien avec les réponses électrochimiques. Une étude de l’écologie de ces biocathodes a alors été menée pour identifier les microorganismes en lien avec ces performances.Enfin, le dernier chapitre de ce travail est consacré à l’exploration du rôle d’électrodes dans les sédiments sur la réduction des nitrates.

• 2024

Microbial electrochemical technology (MET) represents a novel approach demonstrating promising application prospects in emerging strategic industries such as environment protection, energy saving, and sustainable energy production. Among different METs, microbial electrochemical snorkels (MES) are praised for the simple design, high flexibility, and low costs. Several pilot MESs have been employed to mitigate environmental issues in European and American countries. Despite the rapid development, only one review article on MES has been published so far. Here we review the latest achievements in this field and introduce the principles, structures, functions, and applications of MESs. Moreover, we summarize the key challenges and the future research areas in this field, aiming to give insights into the research on MESs and other METs and improve the applications of such technologies.

• 2021

• 2015

• 2019

A microbial electrochemical snorkel (MES) is formed by the direct coupling of a microbial anode with a cathode, which may or may not be biotic. It can be considered as a short-circuited microbial fuel cell. In comparison with a microbial fuel cell, an MES does not produce power but it ensures the highest possible electrochemical reaction rates that the system can support. Although MESs have recently received little research attention, a multitude of possible applications have emerged in the last few years. MESs have recently been shown to be effective for organic matter abatement in wastewater, nitrate removal, decontamination of hydrocarbon-polluted sediments, and soil bioremediation. Other applications are foreseen. Thanks to its extreme simplicity, the MES could offer a real opportunity for short-term scale-up. This mini-review seeks to attract the attention of the research community to the potential of this technology and to propose research to develop it.

• 2025

Abstract The escalating concerns over environmental pollution that is severe and the need for sustainable waste treatment methods have driven significant attention toward finding innovative technological solutions. Microbial fuel cell (MFC) has been identified as a potential approach for sludge treatment and renewable energy production. The MFC is a bio-electrochemical system that is promising environmental remediation technology due to its simple compact design, low cost and renewable energy production. As MFC is a recently developed and emerging technology, limited studies have been reported to provide complete and inclusive analyses. This Systematic Literature Review (SLR) aims to provide a comprehensive evaluation of the efficacy of MFC in the bioremediation of toxic compounds from wastewater sludge. The process of writing this SLR has adhered to the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) writing standard. To search for relevant articles and sources to be included in this SLR, three main databases, namely PubMed, Web of Science and Scopus were utilized with studies spanned from 2003 to 2023. Various types of MFC were evaluated for their bioremediation properties and from the extensive analysis conducted, it could be deduced that dual-chamber MFC is the most effective method of bioremediation due to the presence of two separate chambers. Referring to this SLR, it supports the effectiveness of MFC in bioremediating toxic compounds present in wastewater sludge. In addition, the microbial processes within MFC contribute significantly to the removal or reduction of various contaminants. Graphical abstract

• 2016

• 2011

• 2019

• 2011

• 2012

• 2019

Abstract For mercury phytoextraction, we previously demonstrated in Arabidopsis thaliana that a constitutive and ubiquitous promoter-driven expression of a bacterial mercury transporter MerC fused with SYP121, a plant SNARE for plasma membrane protein trafficking increases plant mercury accumulation. To advance regulation of ectopic expression of the bacterial transporter in the plant system, the present study examined whether merC-SYP121 expression driven by a root epidermis specific promoter (pEpi) is sufficient to enhance mercury accumulation in plant tissues. We generated five independent transgenic Arabidopsis plant lines (hereafter pEpi lines) expressing a transgene encoding MerC-SYP121 N-terminally tagged with a fluorescent protein mTRQ2 under the control of pEpi, a root epidermal promoter. Confocal microscopy analysis of the pEpi lines showed that mTRQ2-MerC-SYP121 was preferentially expressed in lateral root cap in the root meristematic zone and epidermal cells in the elongation zone of the roots. Mercury accumulation in shoots of the pEpi lines exposed to inorganic mercury was overall higher than the wild-type and comparable to the over-expressing line. The results suggest that cell-type specific expression of the bacterial transporter MerC in plant roots sufficiently enhances mercury accumulation in shoots, which could be a useful phenotype for improving efficiency of mercury phytoremediation.

• 2022

• 2013

• 2022

• 2023