Shentan Liu, Hongpu Xue, Xiaojuan Feng et al.

Journal of environmental chemical engineering • 2022

Laura Stricker, Isabella Guido, Thomas Breithaupt et al.

Journal of The Royal Society Interface • 2020

Shewanella oneidensis MR-1 are facultative aerobic electroactive bacteria with an appealing potential for sustainable energy production and bioremediation. They gather around air sources, forming aerotactic bands and biofilms. Here, we experimentally follow the evolution of the band around an air bubble, and we find good agreement with the numerical solutions of the pertinent transport equations. Video microscopy reveals a transition between motile and non-motile MR-1 upon oxygen depletion, preventing further development of the biofilm. We discover that MR-1 can alternate between longitudinal fast and sideways slow swimming. The resulting bimodal velocity distributions change in response to different oxygen concentrations and gradients, supporting the biological functions of aerotaxis and confinement.

Yangyang Yu, Zhen Fang, Lu Gao et al.

Electrochemistry Communications • 2017

Divya Naradasu, Alexis Guionet, Toshinori Okinaga et al.

ChemElectroChem • 2020

Abstract Extracellular electron transfer (EET) via cell‐bound redox enzymes and/or redox shuttles is extensively studied in environmental bacteria. Meanwhile, EET capable pathogens have been identified in the human gut. However, other EET‐capable bacterial niches where possible biofilm infections are prominent have scarcely been explored. Herein, we electrochemically characterized human oral biofilm pathogens, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, to examine their EET capability. Both strains showed current production with the electrode poised at +0.4 V vs. a standard hydrogen electrode, which was associated with a decrease in electron‐donor concentration, coupled with the appearance of oxidative peaks in differential pulse (DP) and cyclic voltammograms (CV). Addition of antibiotics that suppress the biosynthesis of membrane or protein showed a significant current decrease, demonstrating that current production reflects the cellular activity in these pathogens. DPV‐ and CV‐based kinetic analyses supported by transmission electron microscopy of the cells stained for transition metals suggest a potential EET mechanism associated with the presence of redox enzymes on the cell membrane. These results could be the basis to reevaluate human oral pathogens from an electroactive point of view. The identified electrochemical activity of the two strains can be an effective test for assessing the impact of antibacterial compounds on the pathogen cellular activity on an electrode.

Ankit Rao, Anubha Kaushik, Vikrant Singh Rao et al.

Applied Energy • 2024

Yang Yang, Anran Fang, Kun Feng et al.

The Science of The Total Environment • 2020

Keren Yanuka-Golub, Vadim Dubinsky, Elisa Korenblum et al.

mBio • 2021

Microbial fuel cells (MFCs) generate energy while aiding the biodegradation of waste through the activity of an electroactive mixed biofilm. Metabolic cooperation is essential for MFCs' efficiency, especially during early colonization. Thus, examining specific ecological processes that drive the assembly of anode biofilms is highly important for shortening startup times and improving MFC performance, making this technology cost-effective and sustainable. Here, we use metagenomics to show that bioaugmentation of the anode surface with a taxonomically defined electroactive consortium, dominated by Desulfuromonas , resulted in an extremely rapid current density generation. Conversely, the untreated anode surface resulted in a highly stochastic and slower biofilm assembly. Remarkably, an efficient anode colonization process was obtained only if wastewater was added, leading to a nearly complete replacement of the bioaugmented community by Geobacter lovleyi Although different approaches to improve MFC startup have been investigated, we propose that only the combination of anode bioaugmentation with wastewater inoculation can reduce stochasticity. Such an approach provides the conditions that support the growth of specific newly arriving species that positively support the fast establishment of a highly functional anode biofilm. IMPORTANCE Mixed microbial communities play important roles in treating wastewater, in producing renewable energy, and in the bioremediation of pollutants in contaminated environments. While these processes are well known, especially the community structure and biodiversity, how to efficiently and robustly manage microbial community assembly remains unknown. Moreover, it has been shown that a high degree of temporal variation in microbial community composition and structure often occurs even under identical environmental conditions. This heterogeneity is directly related to stochastic processes involved in microbial community organization, similarly during the initial stages of biofilm formation on surfaces. In this study, we show that anode surface pretreatment alone is not sufficient for a substantial improvement in startup times in microbial fuel cells (MFCs), as previously thought. Rather, we have discovered that the combination of applying a well-known consortium directly on the anode surface together with wastewater (including the bacteria that they contain) is the optimized management scheme. This allowed a selected colonization process by the wastewater species, which improved the functionality relative to that of untreated systems.

Mekhaissia Ouis, Mostéfa Kameche, Christophe Innocent et al.

Polymer Bulletin • 2017

Shan Huang, Jingran Zhang, Chuqiao Wang et al.

Journal of environmental chemical engineering • 2022

Eunseo Kim, Min‐Soo Kim, Shuwei Li et al.

Journal of Power Sources • 2024

Hui Wang, Shufang Zeng, Lijun Luo et al.

Environmental Research • 2023

Zhaopeng Qu, Jin Li, Zhi Hu et al.

Chemical Engineering Journal • 2023

Alexiane Godain, Timothy M. Vogel, Pascal Fongarland et al.

Bioengineering • 2023

This investigation examined the role of shear stress on the dynamic development of microbial communities within anodic biofilms in single-chamber microbial fuel cells (MFCs). Bacterial attachment to surfaces, often regarded as a crucial step in biofilm formation, may significantly contribute to the selection of electroactive bacteria (EAB). It is well established that hydrodynamic forces, particularly shear forces, have a profound influence on bacterial adhesion. This study postulates that shear stress could select EAB on the anode during the adhesion phase by detaching non-EAB. To examine this hypothesis, MFC reactors equipped with a shear stress chamber were constructed, creating specific shear stress on the anode. The progression of adhesion under various shear stress conditions (1, 10, and 50 mPa) was compared with a control MFC lacking shear stress. The structure of the microbial community was assessed using 16S rRNA gene (rrs) sequencing, and the percentage of biofilm coverage was analyzed using fluorescence microscopy. The results indicate a significant impact of shear stress on the relative abundance of specific EAB, such as Geobacter , which was higher (up to 30%) under high shear stress than under low shear stress (1%). Furthermore, it was noted that shear stress decreased the percentage of biofilm coverage on the anodic surface, suggesting that the increase in the relative abundance of specific EAB occurs through the detachment of other bacteria. These results offer insights into bacterial competition during biofilm formation and propose that shear stress could be utilized to select specific EAB to enhance the electroactivity of anodic biofilms. However, additional investigations are warranted to further explore the effects of shear stress on mature biofilms.

G.A. Huerta-Miranda, Alonso I. Arroyo-Escoto, X. Burgos et al.

Bioelectrochemistry • 2019

Tyler Arbour, Benjamin Gilbert, Jillian F. Banfield

Frontiers in Microbiology • 2020

Extracellular electron transfer (EET) between microbes and iron minerals, and syntrophically between species, is a widespread process affecting biogeochemical cycles and microbial ecology. The distribution of this capacity among microbial taxa, and the thermodynamic controls on EET in complex microbial communities, are not fully known. Microbial electrochemical cells (MXCs), in which electrodes serve as the electron acceptor or donor, provide a powerful approach to enrich for organisms capable of EET and to study their metabolism. We used MXCs coupled with genome-resolved metagenomics to investigate the capacity for EET in microorganisms present in a well-studied aquifer near Rifle, CO. Electroactive biofilms were established and maintained for almost four years on anodes poised mostly at -0.2 to -0.25 V vs. SHE, a range that mimics the redox potential of iron-oxide minerals, using acetate as the sole carbon source. Here we report the metagenomic characterization of anode-biofilm and planktonic microbial communities from samples collected at timepoints across the study period. From two biofilm and 26 planktonic samples we reconstructed draft-quality and near-complete genomes for 84 bacteria and 2 archaea that represent the majority of organisms present. A novel Geobacter sp. with at least 72 putative multiheme c-type cytochromes (MHCs) was the dominant electrode-attached organism. However, a diverse range of other electrode-associated organisms also harbored putative MHCs with at least 10 heme-binding motifs, as well as porin-cytochrome complexes and e-pili, including Actinobacteria, Ignavibacteria, Chloroflexi, Acidobacteria, Firmicutes, Beta- and Gammaproteobacteria. Our results identify a small subset of the thousands of organisms previously detected in the Rifle aquifer that may have the potential to mediate mineral redox transformations.

Yaoli Wei, Liying Zhang, Bin Liang et al.

Environmental Science & Technology • 2024

Synergistic control of the risks posed by emerging antimicrobials and antibiotic resistance genes (ARGs) is crucial for ensuring ecological safety. Although electrogenic respiration can enhance the biodegradation of several antimicrobials and reduce ARGs accumulation, the association mechanisms of antimicrobial biodegradation (trimethoprim, TMP) with the fate of the antimicrobial resistome remain unclear. Here, the biotransformation pathway of TMP, microbial associations, and functional gene profiles (e.g., degradation, antimicrobial resistance, and electron transfer) were analyzed. The results showed that the microbial electrogenic respiration significantly enhanced the biodegradation of TMP, especially with a cosubstrate sodium acetate supply. Electroactive bacteria enriched in the electrode biofilm positively correlated with potential TMP degraders dominated in the planktonic communities. These cross-niche microbial associations may contribute to the accelerated catabolism of TMP and extracellular electron transfer. Importantly, the evolution and dissemination of overall ARGs and mobile genetic elements (MGEs) were significantly weakened due to the enhanced cometabolic biodegradation of TMP. This study provides a promising strategy for the synergistic control of the water ecological risks of antimicrobials and their resistome, while also highlighting new insights into the association of antimicrobial biodegradation with the evolution of the resistome in an electrically integrated biological process.

Leo Huan-Hsuan Hsu, Yixin Zhang, Pu Deng et al.

Nano Letters • 2019

Electron transport in biological and inorganic systems is mediated through distinct mechanisms and pathways. Their fundamental mismatch in structural and thermodynamic properties has imposed a significant challenge on the effective coupling at the biotic/abiotic interface, which is central to the design and development of bioelectronic devices and their translation toward various engineering applications. Using electrochemically active bacteria, such as G. sulfurreducens , as a model system, here we report a bottom-up, biosynthetic approach to synergize the electron transport and significantly enhance the coupling at the heterogeneous junction. In particular, graphene oxide was exploited as the respiratory electron acceptors, which can be directly reduced by G. sulfurreducens through extracellular electron transfer, closely coupled with outer membrane cytochromes in electroactive conformation, and actively "wire" the redox centers to external electrical contacts. Through this strategy, the contact resistance at the biofilm/electrode interface can be effectively reduced by 90%. Furthermore, the cyclic voltammetry reveals that the electron transfer of the DL-1 biofilm transformed from a low-current (∼0.36 μA), rate-limited profile to a high-current (∼5 μA), diffusion-limited profile. These results suggested that the integration of rGO can minimize the charge transfer barriers at the biofilm/electrode interface. The more transparent contact at the DL-1/electrode interface also enables unambiguous characterization of the inherent electron transport kinetics across the electroactive biofilm independent of cell/electrode interactions. The current work represents a strategically new approach toward the seamless integration of biological and artificial electronics, which is expected to provide critical insights into the fundamentals of biological electron transport and open up new opportunities for applications in biosensing, biocomputing, and bioenergy conversion.

Yuqiao Dong, Danqing Feng, Guang‐Ling Song et al.

The Science of The Total Environment • 2022

Jixiang Zou, Qinghuan Chang, Chongshen Guo et al.

Journal of Environmental Management • 2023

Krzysztof Karoń, Ewa Zabłocka-Godlewska, Katarzyna Krukiewicz

Electrochimica Acta • 2022

A rapid technological advancement observed in recent decades has indicated the urgent need for the development of robust and efficient energy storage devices. An interesting concept that has just emerged in the literature describes the use of biologically-derived materials, particularly living electroactive bacterial biofilms, for the development of supercapacitors. The aim of this paper is to present a recent state-of-the art in the field of bacteria-based supercapacitors, indicating current limitations and future opportunities of this microbial electrotechnology. Starting from a brief characterization of electrochemically active bacteria, we describe the mechanism of electron transfer in biofilms, identify structural units responsible for electron transfer, characterize supercapacitive properties of bacteria as confirmed by different measuring techniques, and provide a summary of recent literature studies employing bacteria, either in a living or in a mineralized form, in the design of novel supercapacitors. In the last section, we indicate the most important issues that need to be resolved to allow for the practical implementation of bacteria-based supercapacitors in energy storage applications.

Yanan Bai, Fang Zhang, Linpeng Yu et al.

The Science of The Total Environment • 2021

M. Mejía‐López, O. Lastres, José Luis Alemán-Ramírez et al.

Biochemical Engineering Journal • 2023

Vitor Cano, Marcelo Antunes Nolasco, Halil Kurt et al.

The Science of The Total Environment • 2023

Ying Zhang, Caicai Lu, Zhi Chen et al.

The Science of The Total Environment • 2021

Yuanfeng Liu, Yaxin Sun, Min Zhang et al.

Journal of Colloid and Interface Science • 2022

Ningyuan Zhu, Xuechen Zhang, Shanshan Yang et al.

ACS Earth and Space Chemistry • 2021

Photic biofilms widely exist on the surface of paddy soil and play a key role in nutrient transformation and accumulation in the soil–water interface. However, whether and how photic biofilms affect nitrogen cycles in the subsoil remained unclear. This study investigated the processes and mechanisms of nitrate reduction in waterlogged paddy soil in the presence (treatment) or absence (control) of photic biofilms. The observed nitrate reduction rate constant (kobs) in the treatment soil increased 1.7 times compared with control. This accelerated kobs was attributed to the synergistic effect between poorly crystalline Fe minerals and autotrophic denitrifiers in soil, which was highly related to the presence of the photic biofilms. Photic biofilms aggravating daily redox oscillations at the soil–water interface promoted the formation of poorly crystalline Fe minerals available for microorganisms. Thus, photic biofilms increased the relative abundance of electroactive bacteria (Sphingomonadaceae and Xanthobacteraceae), iron reduction bacteria (Geobacter and Ignavibacterium), and denitrifiers (Rhodanobacteraceae and Burkholderiaceae) with higher copy numbers of nirK, nirS, and nosZ genes, thereby accelerating the nitrate reduction. Additionally, poorly crystalline Fe minerals contributed to improving interfacial electron transfer ability, which improved the activity of denitrifiers. These results suggested that the photic biofilms bioelectrochemically mediated the nitrate reduction in the waterlogged paddy soil.

Ioannis Ieropoulos, Oluwatosin Obata, Grzegorz Pasternak et al.

Journal of Industrial Microbiology & Biotechnology • 2019

Microbial fuel cell (MFC) technology is currently gaining recognition as one of the most promising bioenergy technologies of the future. One aspect of this technology that has received little attention is the disinfection of effluents and the fate of pathogenic organisms that find their way into the waste stream. In this study, three independent trials were carried out to evaluate the fate of three bioluminescent pathogenic bacteria (Salmonella enterica serovar Typhimurium, Pseudomonas aeruginosa and Staphylococcus aureus) introduced into the anodic chamber of a urine-fed cascade of 9 MFCs with matured, electroactive biofilms. These are common examples of enteric human pathogens, which could contaminate urine or waste streams. The results showed that the average power generation in the closed circuit cascade reached 754 ± 16 µW, with an average pathogen log-fold reduction of 6.24 ± 0.63 compared to 2.01 ± 0.26 for the open circuit cascade for all three pathogens. The results suggest that the bio-electrochemical reactions associated with electricity generation were the primary driving force for the inactivation of the introduced pathogens. These findings show that pathogenic organisms introduced into waste streams could be inactivated by the power-generating process within the MFC cascade system, thereby preventing propagation and thus rendering the effluent safer for possible reuse.

Xiangming Hu, Feng Wang, Yanyun Zhao et al.

Journal of Cleaner Production • 2023

Jiachen Zhu, Mengmeng Li, Hang Yu et al.

The Science of The Total Environment • 2024

Johannes Erben, Zachary A. Pinder, Malte S. Lüdtke et al.

Frontiers in Microbiology • 2021

The anodic current production of Shewanella oneidensis MR-1 is typically lower compared to other electroactive bacteria. The main reason for the low current densities is the poor biofilm growth on most anode materials. We demonstrate that the high current production of Shewanella oneidensis MR-1 with electrospun anodes exhibits a similar threshold current density as dense Geobacter spp biofilms. The threshold current density is a result of local acidification in the biofilm. Increasing buffer concentration from 10 to 40 mM results in a 1.8-fold increase of the current density [(590 ± 25) μA cm -2 ] while biofilm growth stimulation by riboflavin has little effect on the current production. The current production of a reference material below the threshold did not respond to the increased buffer concentration but could be enhanced by supplemented riboflavin that stimulated the biofilm growth. Our results suggest that the current production with S. oneidensis is limited (1) by the biofilm growth on the anode that can be enhanced by the choice of the electrode material, and (2) by the proton transport through the biofilm and the associated local acidification.

Jiaping Hu, Cuiping Zeng, Guangli Liu et al.

Journal of Cleaner Production • 2023

Liyuan Hou, Rebecca Cortez, Michael E. Hagerman et al.

Microbiology Spectrum • 2024

Understanding the extracellular electron transfer mechanisms of electroactive bacteria could help determine their potential in microbial fuel cells (MFCs) and their microbial syntrophy with redox-active minerals in natural environments. However, the mechanisms of extracellular electron transfer to electrodes by sulfate-reducing bacteria (SRB) remain underexplored. Here, we utilized double-chamber MFCs with carbon cloth electrodes to investigate the extracellular electron transfer mechanisms of Desulfovibrio vulgaris Hildenborough ( Dv H), a model SRB, under varying lactate and sulfate concentrations using different Dv H mutants. Our MFC setup indicated that Dv H can harvest electrons from lactate at the anode and transfer them to cathode, where Dv H could further utilize these electrons. Patterns in current production compared with variations of electron donor/acceptor ratios in the anode and cathode suggested that attachment of Dv H to the electrode and biofilm density were critical for effective electricity generation. Electron microscopy analysis of Dv H biofilms indicated Dv H utilized filaments that resemble pili to attach to electrodes and facilitate extracellular electron transfer from cell to cell and to the electrode. Proteomics profiling indicated that Dv H adapted to electroactive respiration by presenting more pili- and flagellar-related proteins. The mutant with a deletion of the major pilus-producing gene yielded less voltage and far less attachment to both anodic and catholic electrodes, suggesting the importance of pili in extracellular electron transfer. The mutant with a deficiency in biofilm formation, however, did not eliminate current production indicating the existence of indirect extracellular electron transfer. Untargeted metabolomics profiling showed flavin-based metabolites, potential electron shuttles.IMPORTANCEWe explored the application of Desulfovibrio vulgaris Hildenborough in microbial fuel cells (MFCs) and investigated its potential extracellular electron transfer (EET) mechanism. We also conducted untargeted proteomics and metabolomics profiling, offering insights into how DvH adapts metabolically to different electron donors and acceptors. An understanding of the EET mechanism and metabolic flexibility of Dv H holds promise for future uses including bioremediation or enhancing efficacy in MFCs for wastewater treatment applications.

Morgen M Clark, Michael D. Paxhia, Jenna Young et al.

Applied and Environmental Microbiology • 2021

The ability of some metal-reducing bacteria to produce a rough (no O-antigen) lipopolysaccharide (LPS) could facilitate surface interactions with minerals and metal reduction. Consistent with this, the laboratory model metal reducer Geobacter sulfurreducens PCA produced two rough LPS isoforms (with or without a terminal methyl-quinovosamine sugar) when growing with the soluble electron acceptor fumarate but expressed only the shorter and more hydrophilic variant when reducing iron oxides. We reconstructed from genomic data conserved pathways for the synthesis of the rough LPS and generated heptosyltransferase mutants with partial (Δ rfaQ ) or complete (Δ rfaC ) truncations in the core oligosaccharide. The stepwise removal of the LPS core sugars reduced the hydrophilicity of the cell and increased outer membrane vesiculation. These changes in surface charge and remodeling did not substantially impact planktonic growth but disrupted the developmental stages and structure of electroactive biofilms. Furthermore, the mutants assembled conductive pili for extracellular mineralization of the toxic uranyl cation but were unable to prevent permeation and mineralization of the radionuclide in the cell envelope. Hence, not only does the rough LPS promote cell-cell and cell-mineral interactions critical to biofilm formation and metal respiration but it also functions as a permeability barrier to toxic metal cations. In doing so, the rough LPS maximizes the extracellular reduction of soluble and insoluble metals and preserves cell envelope functions critical to the environmental survival of Geobacter bacteria in metal-rich environments and their performance in bioremediation and bioenergy applications. IMPORTANCE Some metal-reducing bacteria produce an LPS without the repeating sugars (O-antigen) that decorate the surface of most Gram-negative bacteria, but the biological significance of this adaptive feature was not previously investigated. Using the model representative Geobacter sulfurreducens strain PCA and mutants carrying stepwise truncations in the LPS core sugars, we demonstrate the importance of the rough LPS in the control of cell surface chemistry during the respiration of iron minerals and the formation of electroactive biofilms. Importantly, we describe hitherto overlooked roles for the rough LPS in metal sequestration and outer membrane vesiculation that are critical for the extracellular reduction and detoxification of toxic metals and radionuclides. These results are of interest for the optimization of bioremediation schemes and electricity-harvesting platforms using these bacteria.

Jianliang Xue, Han Ma, Xing Dong et al.

Journal of Hazardous Materials • 2024

Hongwei Chen, Chao Zhao, Yangfan Song et al.

Journal of Power Sources • 2022

Yang Yang, Anran Fang, Kun Feng et al.

The Science of The Total Environment • 2022

Jaecheul Yu, Evy Widyaningsih, Young-Hyun Park et al.

The Science of The Total Environment • 2020

Alex J. Robb, Sergey M. Vinogradov, Allison S. Danell et al.

Electrochimica Acta • 2018

Qi Huang, Basem S. Zakaria, Yingdi Zhang et al.

Water Environment Research • 2020

Anaerobic bioreactors for source-separated blackwater are mostly operated at low organic loading rates (OLRs) due to low biodegradability and the potential of ammonia inhibition. In this study, an anaerobic biofilm reactor having conductive carbon fibers as the media was investigated for the high-rate treatment of blackwater collected from vacuum toilets. The bioreactor was operated at different OLRs ranged from 0.77 to 3.01 g COD/L-d in four stages for a total operating period of ~ 250 days. With the increase of OLRs, the specific methane production rate increased from 105.3 to 304.6 ml/L-d with high methane content in biogas (75.5%-83%). The maximum methane yield was achieved at hydraulic retention time (HRT) of 15 days. Highest organics and suspended solids removal (80%-83%) were achieved at 20-days HRT, while increased OLRs resulted in diminished removal efficiencies. The state variables, including pH, total ammonia nitrogen, short-chain volatile fatty acids, and soluble chemical oxygen demand, indicated the system had a great capability to withstand the high OLRs. Microbial community analysis revealed that the high performance might be attributed to direct interspecies electron transfer (DIET) facilitated by potentially electroactive bacteria (e.g., Syntrophomonas, Clostridium) and electrotrophic archaea (e.g., Methanosaeta and Methanosarcina species) enriched on the carbon fibers. PRACTITIONER POINTS: An anaerobic biofilm reactor was investigated for biomethane recovery from source-separated blackwater. Conductive carbon fibers were utilized as the media to stimulate enrichment of potentially electroactive methanogenic communities. The bioreactor was operated at ambient temperature for over 250 days. High methane production rate and high-quality biogas were achieved at OLRs ranged from 0.77 to 3.01 g COD/L-d. Microbial community analysis suggested direct interspecies electron transfer (DIET) between specific electroactive bacteria and electrotrophic archaea.

Insaf Tou, Yamina Mounia Azri, Meriem Sadi et al.

Biomass Conversion and Biorefinery • 2020