Boyu Lyu, Bharat Manna, Xueyang Zhou et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2024

Abstract Organic micropollutants (OMPs) in wastewater present significant environmental challenges, but effective removal strategies are hindered by our limited understanding of their co-metabolic biodegradation. We aim to elucidate the microbial enzymes, metabolic pathways, and community members involved in OMP co-metabolic degradation, thereby paving the way for more effective wastewater treatment strategies. We integrated multi-omics (metagenomics, metaproteomics, and metabolomics) and functional group analysis to investigate 24 OMPs under three aeration conditions. Our findings reveal that oxidoreductases, particularly cytochrome P450s and peroxidases, are crucial for recalcitrant OMPs containing halogen groups (-Cl, -F) like fluoxetine and diuron. Hydrolases, including amidases, are instrumental in targeting amide-containing (-CONH₂) OMPs such as bezafibrate and carbamazepine. Regarding microbial metabolism involved in OMP co-metabolic degradation, we found that amino acid metabolism is crucial for degrading amine-containing (-NH₂) OMPs like metoprolol and citalopram. Lipid metabolism, particularly for fatty acids, contributes to the degradation of carboxylic acid (-COOH) containing OMPs such as bezafibrate and naproxen. Finally, with Actinobacteria , Bacteroidetes , and Proteobacteria emerging as primary contributors to these functionalities, we established connections between OMP functional groups, degradation enzymes, metabolic pathways, and microbial phyla. Our findings provide generalized insights into structure-function relationships in OMP co-metabolic degradation, offering the potential for improved wastewater treatment strategies. Graphical abstract

Jianxun Shen, T. Shirey, Adam J. Wyness et al.

Preprints.org • 2020

Over the past 150 million years, the hyperarid core of the Atacama Desert has been transformed by geologic and atmospheric conditions into one of the most unique and inhospitable landscapes on the planet. This makes it an ideal Mars analog that has been explored for decades as preliminary studies on the space life discovery. However, two heavy rainfalls that occurred in the Atacama in 2015 and 2017 provide a unique opportunity to study the response of resident extremophiles to rapid environmental change associated with excessive water and salt shock. Here we combine geochemical analyses with molecular biology to study the variations in salts and microbial communities along an aridity gradient, and to examine the reshuffling of hyperarid microbiomes before and after the two rainfall events. Analysis of microbial community composition revealed that soils within the southern desert were consistently dominated by Actinobacteria, Proteobacteria, Acidobacteria, Planctomycetes, Chloroflexi, Bacteroidetes, Gemmatimonadetes, and Verrucomicrobia; soils within the hyperarid sites were dominated by Aquificae and Deinococcus-Thermus before heavy rainfalls, while these organisms almost totally diminished after rainfall, and the hyperarid microbial consortia and metabolisms transformed to a more southern desert pattern along with increased biodiversity. Salts at the shallow subsurface were dissolved and leached down to a deeper layer, both benefitting and challenging indigenous microorganisms with the excessive input of water and ions. Microbial viability was found to change with aridity and rainfall events but correlated with elevation, pH, conductivity, chloride, nitrate, sulfate, and soil organic matters (SOM). Metagenomic functional pathways related to stressor responses also increased in post-rainfall hyperarid soils. Our findings contribute to the primary goal of Atacama Mars analog research for understanding the microbial community structure and adaptations: this study sheds light on the structure of xerophilic, halophilic, and radioresistant microbiomes in hyperarid environments, and their response to changes in water availability.

Nimrod Wieler, Tali Erickson Gini, O. Gillor et al.

Biogeosciences • 2021

Abstract. Biological rock crusts (BRCs) are ubiquitous features of rock surfaces in drylands composed of slow-growing microbial assemblages. BRC presence is often correlated with rock weathering, soiling effect or mitigating geomorphic processes. However, their development rate is still unknown. In this work, we characterised and dated BRCs in an arid environment, under natural conditions, by integrating archaeological, microbiological and geological methods. To this end, we sampled rocks from a well-documented Byzantine archaeological site and the surrounding area located in the central Negev, Israel. The archaeological site, which is dated to the fourth to seventh centuries CE, was constructed from two lithologies, limestone and chalk. BRC started developing on the rocks after being carved, and its age should match that of the site. Using stable carbon and oxygen isotope ratios, we confirmed the biogenic nature of the crusts. The BRC samples showed mild differences in the microbial community assemblages between the site and its surroundings, irrespective of lithology, confirming the dominance of aeolian inoculation sources. All BRCs were dominated by Actinobacteria, Cyanobacteria and Proteobacteria. We further measured the BRC thickness on 1700-year-old building stone blocks and determined it to be 0.1–0.6 mm thick. Therefore, a BRC growth rate was estimated, for the first time, to be 0.06–0.35 mm kyr −1 . Our dating method was then validated on a similar archaeological site located ca. 20 km away, giving comparable values. We propose that BRC growth rates could be used as an affordable yet robust dating tool in archaeological sites in arid environments.

B. Toshbadalov

American Journal of Applied Science and Technology • 2025

The Kyzylkum Desert represents a unique and extreme ecosystem where plants depend critically on their associated microbiomes for survival and adaptation. This review explores the intricate composition, dynamic interactions, and functional roles of plant microbiomes in such harsh environments, emphasizing their ecological importance and potential applications. Despite significant progress in microbiome research, major gaps remain in understanding the specific mechanisms that enable these microbial communities to thrive under extreme abiotic stressors like high salinity, nutrient deficiency, and drought. Advanced molecular approaches, including metagenomics and 16S rRNA sequencing, are highlighted as indispensable tools for unraveling microbial diversity and functionality in desert ecosystems. Key findings reveal the vital roles of microbial communities—bacteria, fungi, actinomycetes, and archaea—in enhancing nutrient acquisition, improving drought resilience, and mitigating oxidative stress in desert plants. Notably, symbiotic associations such as nitrogen-fixing bacteria, phosphate-solubilizing fungi, and arbuscular mycorrhizal fungi are crucial in facilitating plant survival in the nutrient-poor soils of the Kyzylkum Desert. Furthermore, this review underscores the unique adaptive traits of desert microbiomes, including stress-response proteins, exopolysaccharide production, and osmoprotectants, which collectively sustain plant-microbe interactions under challenging conditions. This review integrates findings from local and international research to bridge critical knowledge gaps and underscores the potential of desert microbiomes for sustainable applications, including bioinoculants, soil health enhancement, and desertification mitigation. These insights pave the way for innovative strategies to harness microbial communities in addressing global challenges in agriculture and ecosystem restoration.

Xiaolan Xue, Jannathan Mamut

Agronomy • 2024

Most research on plant–microbe interactions emphasize the effects of micronutrients on the rhizosphere microbial community structure. However, the influence of seed structures, particularly the radicle sheath, on microbial diversity at the seedling root tips under varying temperatures and humidity has been less explored. This study conducted controlled indoor experiments in the northern desert of Xinjiang to assess the radicle sheath’s impact on microbial community composition, diversity, and function. The results indicated no significant changes in the Chao1 index for bacteria and fungi, but notable differences were observed in the Shannon and Simpson indices (p < 0.05). Under drought conditions, the radicle sheath significantly reduced bacterial infections without affecting fungi. Genus-level analysis showed an increased abundance of specific dominant bacterial groups when the radicle sheath was retained. NMDS analysis confirmed its significant effect on both bacterial and fungal community structures. LEfSe analysis identified 34 bacterial and 15 fungal biomarkers, highlighting the treatment’s impacts on microbial taxonomic composition. Functional predictions using PICRUSt 2 revealed that the radicle sheath facilitated the conversion of CH4 to CH3OH and various nitrogen cycle processes under drought. Overall, the radicle sheath plays a crucial role in maintaining rhizosphere microbial community stability and enhancing the functions of both bacteria and fungi under drought conditions.

Francisco Mateo-Ramírez, H. Addi, F. J. Hernández‐Fernández et al.

Journal of Chemical Technology &amp; Biotechnology • 2017

BACKGROUND The present work explores the catalytic and electric performance of a microbial fuel cell (MFC) implemented with high chemical oxygen demand (COD) industrial wastewater from Spain. The polymer inclusion membrane based on 70% [MTOA][Cl] IL was used as separator and showed a good efficiency in power production and COD removal. RESULTS Outputs of 72% in COD conversion, 200 mV voltage and 32 mW m−3 power density were obtained, demonstrating that slaughterhouse wastewater is a good feedstock for the scale-up of this technology. Furthermore, the effect of the microbial fuel cell on the physical/chemical parameters of the slaughterhouse wastewater was analyzed. The concentration of nitrite, orthophosphate, sulfate and ammonium was reduced by more than half. CONCLUSIONS Air breathing cathode-microbial fuel cells based on polymer ionic liquids inclusion membranes allow the treatment of an industrial and high load slaughterhouse wastewater with good depuration and electrical performance efficiency. © 2016 Society of Chemical Industry

Safa H. Fadhil, Z. Ismail

Bioremediation Journal • 2021

Abstract Algae-photosynthetic microbial fuel cell (PMFC) could be considered as a promising approach for producing purified water. This study assessed the performance of an algae-PMFC continuously operated for 120 days to treat and demineralize real-field slaughterhouse wastewater associated with bioenergy generation. Mixed bacterial species including Pseudomonas and Bacillus as the dominant species were used to inoculate the anodic chamber, whereby Chlorella vulgaris microalgae were used in the cathodic section. The results showed that maximum removal efficiency of the chemical oxygen demand (COD) and ammonium ions from the actual slaughterhouse wastewater were 99.65% and 70%, respectively. Maximum and average recorded power output were 543.28 and 391.42 mW/m2, respectively. Dense growth of both; the biofilm in the anodic compartment as well as Chlorella vulgaris microalgae in the cathodic compartment were clearly observed after 120-days operation. The promising results of this potential approach encourage the application of PMFC for the treatment of slaughterhouse wastewater.

Afşin Çetinkaya, Levent Bilgili

Environmental Research and Technology • 2022

Slaughterhouse wastewater is one of the most produced industrial wastewater in the world and has a high pollution potential, and this wastewater can cause a high level of polluting effect when it is given directly to river beds or sewage systems. Wastewater contains proteins, fats, carbohydrates in the treatment of blood, skin and feathers, which results in much higher biological oxygen demand (BOD) and chemical oxygen content (COD). The possibility of using ultrafiltration for slaughterhouse wastewater treatment was investigated. The results showed that ultrafiltration can be an efficient purification method. COD and BOD5 remova lefficiency is around 96% and 95%. In addition to these results, the Life Cycle Analysis (LCA) of the ultrafiltration system was also carried out. Accordingly, the effects of ultrafiltration system on human health, ecosystem quality, climate change and resources were calculated as 0,00000046 Disability-Adjusted Life Years (DALY), 0,134 PDFxm2yr, 0,336 kg CO2 eq and 6,937 MJ respectively. As a result of the study, it is thought that slaughterhouse wastewater can be used as irrigation water after passing through the ultrafiltration membrane due to the high content of N and P.

Xiaoyu Cong, Peter Krolla, Umer Zeb Khan et al.

Research Square • 2023

Abstract The global spread of antimicrobial resistances is mainly due to the emission of antibiotic-resistant bacteria, antibiotic resistance genes, facultative pathogenic bacteria, and antimicrobial resistance causing substances in human and animal waste into the environment. Innovative strategies are sought to intervene decentrally or centrally at sources of the emergence and spread of hygienically relevant bacteria. In this study, the dissemination of facultative pathogenic bacteria and antibiotic resistance genes of clinical relevance are monitored in the raw effluents from poultry and pig slaughterhouses in combination of some conventional wastewater treatments on site. As an innovation step, the antimicrobial blue light (aBL) in combination with a porphyrin-based photo-enhancer is investigated for decontamination purpose. Facultative pathogenic bacteria from the clinically significant ESKAPE group are used as reference bacteria and examined for the effectiveness of this inactivation strategy. Beside the directed analyses with reference bacteria, a successful application of the combinatory light-based method was also demonstrated using raw sewage from slaughterhouse.

Venko Beschkov, Elena Razkazova-Velkova

Energy Storage Battery Systems - Fundamentals and Applications • 2021

Industrial fermentation and biological wastewater treatment are usually based on redox processes taking place in living cells and on enzyme processes. The practical application of these redox processes is usually associated with electricity generation in microbial fuel cells or process enhancement in microbial electrolysis cells. The microbial fuel cell approach leads to straightforward wastewater treatment with less energy demand. Additional advantages of these processes are the direct removal of various pollutants and the avoidance of addition of chemical agents with the resulting waste products of treatment as it is familiar with the traditional chemical methods. Another option for the use of bioelectrochemical processes in practice is the approach of microbial electrolysis cells. The application of electric field on fermentation or microbial wastewater treatment processes might result in different aspects: either in purely electrochemical processes on the electrodes or in different types of bioelectrochemical stimulation of enzyme activity in the living cells. These applications are associated with the combination of enzyme activity with electrochemical processes to produce or remove certain compounds rapidly at high concentrations with no additions of other chemicals. In the present chapter, both approaches (microbial fuel cells and microbial electrolysis cells) are presented and discussed. Some practical applications and experimental examples of such bioelectrochemical redox processes stimulated by constant electric field are demonstrated.

Sigrid Kusch-Brandt, Mohammad A. T. Alsheyab

J • 2021

A wastewater refinery is a multifunctional solution that combines different technologies and processing schemes to recover a spectrum of valuable materials from municipal or industrial wastewater. The concept of wastewater refinery introduces a new perspective on wastewater treatment and management. It aims at making the most of wastewater constituents by co-producing different worthful outputs, such as water, energy, nitrogen, sulfide, and phosphorous. This can turn the treatment of wastewater from a major cost into a source of profit. The wastewater refinery approach is well aligned with the concept of the circular economy. A case study on Qatar’s wastewater revealed the potential recovery of significant quantities of valuable resources embodied in the country’s wastewater. Valorization of organic constituents and the recovery of nitrogen, phosphorus, and sulfide should be given priority. To facilitate the adoption of the wastewater refinery concept, research is required to explore technical and economic bottlenecks.

Riang Anggraini Rahmanisa, I Nyoman Widiasa

Reaktor • 2020

Spent caustic wastewater is produced from the scrubbing process using a caustic solution to absorb contaminants in the oil stream (hydrocarbon). Indonesia’s Petroleum Oil Refinery produces spent caustic wastewater from LPG and kerosene processing unit. Spent caustic wastewater has the characteristic of a strong odor with very high pH (12-14), containing dangerous pollutants such as phenol, aldehydes, mercaptans, and thiols that can be harmful to the human and environment. The Fenton process is used to treat spent caustic before being discharged to the environment. The Fenton process is one of AOPs (Advanced Oxidation Process) using Fe2+ as a catalyst and H2O2 as an oxidant to oxidize organic contaminants in wastewater. This study aims to determine the operating conditions of the Fenton Process with the target characteristics of treated spent caustic meet the WWTP (Waste Water Treatment Plant) inlet specifications and to make the design process of spent caustic treatment with the Fenton Process capacity of 10 m3/day. By operating at the H2O2/Fe (II) ratio of 1.8, the final target was achieved with COD of 810 ppm, ammonia of 22.84 ppm, sulfide of 60.93 ppm and phenol of 14.56 ppm. Total Capital Investment (TCI) for the design is US$ 2146701.89 whereas Total Manufacturing Cost of US$ 2089740.75.Keywords: spent caustic; refinery wastewater; Fenton process

Global NEST Journal • 2025

&lt;p&gt;The complex composition of persistent and resistant contaminants in oil refinery wastewater presents a significant environmental challenge that conventional treatment methods frequently fail to effectively address. Advanced Oxidation Processes (AOPs), specifically the photo-Fenton method, and a deep learning framework known as the Infallible Deep Neural Network (InfDNN) with a novel activation function known as Infallible Linear Units (InfLU) are the focus of this study's integrated approach. The investigation focused on the removal of polycyclic aromatic hydrocarbons (PAHs) and other pollutants from refinery wastewater.&amp;nbsp; Nine PAHs were found in the GC-MS analysis, including benzo(a)pyrene, phenanthrene, and naphthalene. Before treatment, benzo(a)pyrene and benzo(k)fluoranthene exceeded the CPCB limit of 0.06 g/L. The photo-Fenton process demonstrated high efficiency, with naphthalene levels reduced from 373.47 µg/L to 5.08 µg/L at the Inlet—a 98.6% degradation rate—and phenol completely eliminated at most sampling points (100% removal).&amp;nbsp; Overall, PAH degradation efficiencies ranged from 84.5% to 100%, and partial mineralization was confirmed via Total Organic Carbon (TOC) analysis.&amp;nbsp; Iron (Fe) levels at the effluent discharge point reached 30.00 mg/L, exceeding the IRSGP limit and indicating the need for further treatment.&amp;nbsp; The InfDNN model was trained with the Levenberg–Marquardt algorithm and the Multilayer Perceptron (MLP) architecture. It was validated with normalization in the range [0.2–0.8] using 80% of the data for training and 10% each for testing and validation. This study demonstrates the effectiveness of combining photo-Fenton AOPs with AI-based modeling for scalable, cost-efficient, and regulation-compliant treatment of oil refinery wastewater.&lt;/p&gt;

Asaad Olabi

Water and Environment Journal • 2023

Abstract The efficiency of classical Fenton (CF) and modified Fenton (MF) as well as photo‐Fenton processes in real wastewater treatment of pulp and paper (P&amp;P) mill was investigated in this study. The chemical oxygen demand (COD) was chosen as the reference measurement for evaluating the treatment's efficiency. After determining the optimum parameters for each process, the effect of adding ultrasound (US) on improving treatment efficiency was examined. In addition, kinetic study and phytotoxicity analysis were conducted under optimum conditions for all processes. With pH 4, reaction time 50 min, 1.2 g/L Fe 2+ and 8 g/L H 2 O 2 dosages, the best removal efficiency (RE) of COD was determined to be 82.18% in CF process, and this rate rose to 90.1% when US was added. The best RE in MF process was 84.16% with the application of UV‐C, pH 4, reaction time 50 min, 1 g/L Fe 0 and 8 g/L H 2 O 2 doses, although it increased to 93.4% when US was applied. The greatest results in the seed germination test were achieved in US processes with 100% of germination percentage (GP) for spinach and tomato and 90% for cress. In the economic evaluation, when conducting the treatment without US, the estimated relative cost decreased in a 15 and 16%, for CF/UV‐C and CF processes respectively, whereas the CF process was 64% cheaper than the MF process in all applications. The US contributed to enhanced water treatment efficiency by having a significant synergistic impact on Fenton applications. Hence, the combination of photo‐Fenton and ultrasound to treat effluent from P&amp;P mills proved to be an effective and promising technique.

María Cristina Yeber, Tatiana Silva

Water • 2022

High-colored wastewater generated during the cellulose bleaching process causes the inhibition of biological activity when released into the environment. This study aimed to evaluate the bacterium’s capacity, identified as RGM2262, to degrade a complex phenolic structure such as lignin, which is found in high concentrations in the effluents generated during the production of cellulose, raw material for the manufacture of paper. To determine the values of the experimental variables that allow for a greater degradation of organic matter, an experimental model was carried out through experimental design. Thus, the experimental matrix was obtained with the variables pH 7 (−1) to 9 (+1) and a treatment time of 1 day (−1) to 5 days (+1). The results show that, at pH 8 and pH 9, both treatments—with bacteria in bio-films and without bio-films—were efficient. On the second day of treatment, 100% of the color and the phenolic structure were removed, with a similar rate constant, and at the same time, 80% COD and 70% of TOC, respectively.

Humayun Iqbal, Arup Bhowmik, Sabina Yasmin et al.

Research Square • 2022

Abstract Bioelectrochemical systems are a new secondary effluent treatment method where bacteria degrade industrial sludge and generate electricity for the external circuit. In this study, paper industry wastewater effluents were treated in microbial fuel cells (MFCs) by utilising six different sets of electrodes to produce bioelectricity. Bacterial biofilms were studied by field emission scanning electron microscopy (FESEM). Investigation disclosed that zinc mesh and carbon plate (MFC-2) had the highest power generation as observed with 1193 mV of output voltage, 2.69 mA output current and 533 mW/m2 power density along with 92% BOD removal without electrolyte solution. The lowest 325 mV of output voltage, 0.15 mA of output current and 7.0 mW/m2 of power density with 37% removal of BOD were measured for MFC-3, which was constructed with Al mesh and carbon plate. A total of 1.0 M CuSO4.5H2O cathodic electrolyte solution was added in MFC-5 with zinc and copper plates as electrodes, which enhanced the power generation and BOD removal. The highest output voltage, current and power density were obtained for MFC-5 with the magnitude of 1185 mV, 4.79 mA and 939 mW/m2, respectively.

Laleh Mahmoudian-Boroujerd, Ayoub Karimi-Jashni, Sama Azadi

Research Square • 2024

Abstract Pulp and paper mill wastewater treatment poses a significant challenge due to the presence of numerous refractory pollutants, necessitating the need for effective treatment methods. This study aims at multiobjective optimization of an anaerobic baffled reactor (ABR) combined with an activated sludge reactor (ASR) for pulp and paper wastewater treatment. The optimization approach minimizes the hydraulic retention time (HRT) while maximizing the ABR system's organic loading rate (OLR) and COD and BOD removal efficiency. Optimization efforts identified the optimum conditions for the ABR as an OLR of 6.2 g/L/d and an HRT of 3.2 d. Under these conditions, the remarkable COD removal efficiency of 92% and BOD removal efficiency of 95% were achieved in the ABR, demonstrating the system's robust performance in reducing the pollutant load of the wastewater. The integrated ABR-ASR also exhibited outstanding removal efficiencies for various parameters in the optimum conditions. Specifically, COD, BOD, TSS, turbidity, and color displayed removal efficiencies of 95%, 97%, 92%, 98%, and 92%, respectively. These findings underscore the versatility of the integrated system in addressing a spectrum of pollutants present in pulp and paper wastewater. Furthermore, the rate of substrate consumption was investigated using the modified Stover-Kincannon model. The saturation value constant (K B ) and the maximum utilization rate (Umax) values for ABR were found to be 7.95 g/L/d and 5.5 g/L/d, respectively, while for ASR, these values were 0.69 g/L/d and 0.15 g/L/d. This research advances our understanding of the synergistic potential of the ABR-ASR in treating high-strength industrial wastewater.

Torsten Meyer, Minqing Ivy Yang, Camilla Nesbø et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2023

Abstract Amplicon sequencing data and operating data from anaerobic wastewater treatment plants from three Canadian pulp and paper mills were explored using correlation and network modularization approaches to study the microbial community organization and identify relationships between organisms and operating conditions. Each of the digesters contain two or three modules consisting of organisms that cover all trophic stages of anaerobic digestion. These modules are functioning independently from each other, and their relative abundance changes in response to varying operating conditions. The time delay between a change in digester operation and the change in the abundance of microorganisms was investigated using time-lagged operating parameters. This time delay ranged between two to four days and is likely influenced by the growth rates of the anaerobic microorganisms and the digester hydraulic retention time. Digester upsets due to plant shutdown periods and organic overload caused a drastic increase in the population of acetoclastic methanogens, acidogenic fermenters, and syntrophic acid degraders. As a response to impaired process conditions, the same Methanothrix amplicon sequence variant (ASV) dominated methanogenesis in the digesters of all three mills. The common characteristics of the organisms represented by this ASV should be further investigated for their role in alleviating the impact of digester upset conditions. Abstract Figure

Zakari David Adeiza

Nutrition and Food Processing • 2024

Microbial interactions play a crucial role in the functioning and dynamics of ecosystems. These interactions encompass the complex associations among various microorganisms, such as bacteria, fungus, archaea, and viruses. Comprehending microbial interactions is essential for comprehending the intricacy of ecosystems, as well as for exploiting their potential in diverse domains, including agriculture, medicine, and biotechnology. This review provides a thorough examination of microbial interactions, including their various kinds, processes, ecological significance, and practical applications. Microbial interactions are essential in changing ecosystems and have substantial consequences for fields including agriculture, medicine, and biotechnology. Streptomyces, a group of thread-like bacteria, is renowned for its exceptional capacity to synthesise secondary metabolites with a wide range of biological properties. This review article seeks to investigate the complex microbial interactions involving Streptomyces and the consequences of these interactions on environmental and human well-being.

Mesut Yılmazoğlu

Algal Biotechnology for Fuel Applications • 2022

Since MFC degrades simple carbohydrates i.e. glucose, acetate, andbutyrate, and countless organic substances such as pig wastewater, domesticwastewater, and manure sludge waste, the biochemical energy generated by thecatalytic reactions of microorganisms and converts the waste produced into energy. Itpromises a sustainable wastewater treatment to balance the operating cost. This chapteris a review of the advantages of microbial fuel cell treatment of food industrywastewater, which creates high organic pollution in the industrial field.

Jayanthi Velayudhan, Sangeetha Subramanian

Nanotechnology • 2024

Abstract Microbial fuel cells (MFCs) can generate electricity by breaking down organic molecules through sustainable bio-electrochemical processes and wastewater as an energy source. A novel approach to remediate wastewater containing selenite was studied utilizing a selenite-reducing mixed bacterial culture with a nano manganese oxide modified cathode in the MFCs. The modification enhanced electrochemical catalytic activity, extracellular electron transfer rate, chemical oxygen demand (COD) elimination efficiency, and coulombic efficiency. Scanning electron microscopy and energy dispersive x-rays analysis were used to examine a manganese dioxide-coated graphite cathode’s surface morphology and chemical composition. The manganese dioxide-coated electrode generated up to 69% higher voltage with 150 ppm selenite concentration than the uncoated graphite electrode. The MFC removed up to 80% of the initial COD of 120 mg l −1 and achieved a maximum power density of 1.51 W m −2 . The study demonstrates that MFCs can effectively treat selenite-containing wastewater, and modifying the cathode can enhance energy production.

Eduardo González‐Martínez, David A. González‐Martínez, Jose M. Moran‐Mirabal

Advanced Sensor Research • 2024

Abstract Cost‐effective miniaturized electrodes that maintain a high electroactive surface area (ESA) are needed for the widespread deployment of point‐of‐care sensors. Cost‐effective methods are recently developed to fabricate nanoroughened microstructured gold electrodes (NR‐MSEs) with ultrahigh ESA. In this work, the effectiveness of NR‐MSEs for bioelectrochemical enzymatic sensors is evaluated. A glucose sensor is constructed by first casting onto NR‐MSEs a solution containing reduced graphene oxide decorated with gold nanoparticles, glucose oxidase, and glutaraldehyde, followed by a solution containing ferrocene, and a layer of chitosan to prevent the leakage of sensor components. A urea biosensor is also fabricated using Nafion as a cationic exchanger for the electropolymerization of polyaniline, followed by the deposition of a composite containing urease, bovine serum albumin, and glutaraldehyde. The limit of quantification for both biosensors is below clinically relevant concentrations of the analytes in biofluids, 0.67 m m for glucose and 1.70 m m for urea. The sensors exhibit excellent performance in complex matrixes (human blood serum and wine for glucose and human blood serum and urine for urea), with recovery for spiked analytes in the range of 92–108%. It is anticipated that NR‐MSEs will expedite the development of highly sensitive bioelectrochemical sensors for use in resource‐limited settings.

Shivani Maddirala, Sudipa Bhadra, Md. Salatul Islam Mozumder et al.

Processes • 2024

Environmental pollution and energy scarcity are the two significant issues that could substantially impede the sustainable growth of our civilization. Microbial fuel cells (MFCs) are an emerging technique for converting the chemical energy of organic wastes directly into electric energy, allowing for both energy recovery and environmental rehabilitation. Solid organic waste decomposition is generally more challenging compared to organic wastewater due to several factors, including the nature of the waste, the decomposition process, and the associated environmental and logistical considerations. With rapid population expansion and acceleration of urbanization, waste generation continues to rise globally, causing complicated environmental, socioeconomic, and energy problems and a growing demand for public health globally. Bioelectrochemical systems (BES) are promising solid waste management options. However, BES may not be the most effective solution on its own for certain types of waste or may be incapable of treating all waste components. In many circumstances, combining BES with other solid treatment technologies can increase overall treatment efficiency and waste management. Combining BES with other solid treatment methods can have synergistic effects, boosting waste treatment efficiency, resource recovery, and environmental sustainability. However, to guarantee the successful integration and optimization of these combined approaches, site-specific factors, waste characteristics, and system compatibility must be considered.

Sofia Babanova, Jason Jones, Kelly Wiseman et al.

Frontiers in Chemical Engineering • 2022

This study presents BioElectrochemical Treatment Technology (BETT) as a new wastewater management solution toward the Net-Zero future. The results reported herein were collected from a BETT pilot system installed at a large brewery in Los Angeles, CA, United States processing 0.6 m 3 . day -1 of raw brewery wastewater with a high content of fruit pulp. Removal of Chemical Oxygen Demand (COD), Total Suspended Solids (TSS) and protein in mg.L -1 per day or percentage were evaluated over 2 months of continuous operation of the Demo Unit. The GHG emissions associated with the power consumed, biomass produced, and carbon dioxide emitted were estimated and compared to aerobic and anaerobic solutions. It was demonstrated that BETT can process wastewater with higher organic load than most conventional anaerobic systems. The inflow COD loading varied between 48,550 mg/L to 116,200 mg/L, and BETT achieved up to 33% COD removal in 4-h HRT. The TSS removal reached values as high as 79% with incoming TSS concentrations up to 34,000 mg/L TSS. BETT did not directly generate methane and demonstrated 89 and 49% lower landfill methane emissions than aerobic and anaerobic technologies, respectively. The overall reduction in CO 2 emissions, both direct and indirect, was estimated to be 85–90% compared to existing practices.

Louis‐B. Jugnia, Dominic Manno, Jie Sui et al.

The Canadian Journal of Chemical Engineering • 2025

Abstract In this study, removal of dissolved organic carbon and naphthenic acids (NAs) from oil sands process‐affected water (OSPW) was evaluated in flow‐through microbial fuel cell (MFC), microbial electrolysis cell (MEC), and microbial electrosynthesis (MES) cell setups with aerated cathodic compartments. At a hydraulic retention time of 2.4 days, the MEC and MFC setups demonstrated 79% and 4.0% removal efficiency of organic materials, respectively, with corresponding degradation rates of 27.25 and 1.86 mg (L R day) −1 (R = total reactor volume). NAs removal was also significantly higher in the MEC operated at 1.4 V with 54% and 21% removal for the MEC and MFC setups, respectively. Furthermore, once the MEC applied voltage was increased to 2 V (MES mode), NAs removal was further improved, reaching 70% efficiency. Analysis of microbial community composition using 16S rRNA gene amplicon sequences indicated the presence of known electroactive species and microbial populations capable of degrading hydrocarbons and NAs.

Liesa Pötschke, Philipp Huber, Georg Stegschuster et al.

Frontiers in Chemical Engineering • 2022

Commercial carbon fiber (CF) fabrics are popular electrode materials for bioelectrochemical systems (BES), but are usually not optimized for the specific application. This study investigates BES-relevant material characteristics on fabric level, such as weave types and weave parameters. The two contrasting weave types plain and leno weave were characterized with respect to their envisaged application types: 1) BES with mainly advective flow regimes and 2) stirred systems, which could benefit from fluid flow through a fabric electrode. Experiments with batch and continuously fed pure cultures of Geobacter sulfurreducens PCA and Shewanella oneidensis MR-1 reveal that µm-scale electrode topologies are of limited use for the thick biofilms of G. sulfurreducens , but can boost S. oneidensis ’ current generation especially in batch and fed-batch reactors. For advective flow regimes, deeper layers of biofilm inside microporous electrodes are often mass transport limited, even with thin biofilms of S. oneidensis . Therefore, low porosity plain weave electrodes for advective flow operation as in wastewater treating BES should be thin and flat. A trade-off between maximized current density and electrode material utilization exists, which is optimized exemplarily for an advective flow operation. For stirred BES of biotechnological applications, a flow-through of electrolyte is desired. For this, leno weave fabrics with pores at cm-scale are produced from 100% CF for the first time. In a preliminary evaluation, they outperform plain weave fabrics. Mass transfer investigations in stirred BES demonstrate that the large pores enable efficient electrode utilization at lower power input in terms of stirring speed.

Yohanna Anisa Indriyani, Iman Rusmana, Syaiful Anwar et al.

Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) • 2023

The application of microbial fuel cells is still facing some challenges due to its low power output and high internal resistance. It is desirable to obtain a stable and consistent power output from an MFC to support practical real-world applications. Five electroactive bacteria (isolate LGf1, LGf11, LGf15, LGf20, and LGf22) isolated from the sediment of Waduk Saguling were exploited as the potential anodic biocatalyst for MFC, and the performance of these MFCs were studied in terms of voltage generation (open and close circuit), power density and the losses (polarization technique), and efficiencies (coulombic and energy). MFC biocatalyst by isolate LGf11 performed the best electrochemical performances, including highest OCV (open circuit voltage) value (804 mV) and power output (0.043 W/m2), lowest ohmic resistance (475 Ω), and highest coulombic efficiency (75.79%) and energy efficiency (88.36%) among all anodic biocatalysts. Nevertheless, all the five isolates were potential to be exploited as active biocatalyst for MFC due to their high OCV values and the stability of voltage generations, both in open circuit and close circuit mode. The development of system configuration and the use of more suitable substrate for different electroactive microbes in order to harvest more power output was recommended for further study. Utilization of these potential microbes for other applications in MFC (such as wastewater treatment etc.) was also suggested for further research. Keywords: Bio-electrochemical system, Biofuel, Efficiency, Electro-microbiology, Power output

Madiha Tariq, Jin Wang, Zulfiqar Ahmad Bhatti et al.

Processes • 2021

Microbial fuel cells (MFCs) are a recent biotechnology that can simultaneously produce electricity and treat wastewater. As the nature of industrial wastewater is very complex, and it may contain a variety of substrates—such as carbohydrates, proteins, lipids, etc.—previous investigations dealt with treatment of individual pollutants in MFCs; the potential of acetic acid, sucrose, albumin, blood, and their mixture has rarely been reported. Hence, the current investigation explored the contribution of each substrate, both separately and in mixture. The voltage generation potential, current, and power density of five different substrates—namely, acetic acid, sucrose, albumin, blood, and a mixture of all of the substrates—was tested in a dual-chambered, anaerobic MFC operated at 35 °C. The reaction time of the anaerobic batch mode MFC was 24 h, and each substrate was treated for 7 runs under the same conditions. The dual-chambered MFC consisted of anode and cathode chambers; the anode chamber contained the biocatalyst (sludge), while the cathode chamber contained the oxidizing material (KMnO4). The maximum voltage of 769 mV was generated by acetic acid, while its corresponding values of current and power density were 7.69 mA and 347.85 mW, respectively. Similarly, being a simple and readily oxidizable substrate, acetic acid exhibited the highest COD removal efficiency (85%) and highest Coulombic efficiency (72%) per run. The anode accepted the highest number of electrons (0.078 mmol/L) when acetic acid was used as a substrate. The voltage, current, and power density generated were found to be directly proportional to COD concentration. The least voltage (61 mV), current (0.61 mA), and power density (2.18 mW) were observed when blood was treated in the MFC. Further research should be focused on testing the interaction of two or more substrates simultaneously in the MFC.

Rickelmi Agüero-Quiñones, Zairi Ávila-Sánchez, Segundo Rojas-Flores et al.

Sustainability • 2023

The growing global energy demand drives the need to develop new clean energy technologies. In this context, microbial fuel cells (MFC) are one of the emerging technologies with great potential for eco-friendly energy generation; however, the correct choice of electrode material is a significant limitation in the optimal configuration of MFCs. Therefore, this research evaluated the efficiency of activated carbon (AC) anode electrodes for bioenergy production in MFC using synthetic wastewater as a substrate. Peak values of voltage (1120 ± 0.050 mV), current (4.64 ± 0.040 mA), power density (208.14 ± 17.15 mW/cm2), and current density (5.03 A/cm2) were generated, and the Rint obtained was 214.52 ± 5.22 Ω. The substrate was operated at pH values from 5.31 to 7.66, maximum ORP values (858 mV) were reached, and turbidity was reduced to 25.11 NTU. The SEM-EDS (scanning electron microscopy–energy-dispersive X-ray spectroscopy) analyses allowed us to observe the morphology and composition of the AC electrodes, revealing a predominance of O, C, Si, Al, Fe, K, and Ca. It is concluded that the AC electrodes have the potential to produce bioenergy at a laboratory by means of MFC.

Bustami Ibrahim

International Journal of Agriculture and Biology • 2024

Microbial fuel cells (MFCs) generate electrical energy using microorganisms as biocatalysts to convert the chemical bonds of organic compounds in wastewater into electricity. Specific types of electrogenic bacteria that form biofilms on MFC electrodes when exposed to high-protein fish-processing wastewater have not been reported. The purpose of this study was to isolate and determine the characteristics of biofilm bacteria on the microbial fuel cell electrodes and identify the selected bacterial isolates. The bacterial growth media used were nutrient agar (NA), deMAnn Rogosa Sharpe Agar (MRSA), and thioglycollate agar (TGA). The characterization of the bacterial isolates included Gram staining, shape, protease activity, catalase activity, and motility. The selected isolates representing each medium and electrode were identified by PCR. Thirteen isolates were gram-positive with distinct characteristics. Molecular identification of the six selected isolates showed that the K1B isolate was Pediococcus pentosaceus; A1G, A2G and K1G isolates were Pediococcus acidilactici; A1T2 isolate was Bacillus subtilis and A3T2 isolate was Staphylococcus warneri.

Matthew Ferby, Shiqiang Zou, Zhen He

Water Environment Research • 2022

Abstract Microbial fuel cells (MFCs) and forward osmosis (FO) are both attractive and versatile wastewater treatment technologies that possess disadvantageous qualities that prevent their optimal performance. This study aimed to investigate how draw solute selection for FO treatment would affect MFC performance in a coupled FO‐MFC system. Two types of draw solutes, NH 4 HCO 3 and NaCl, were studied, and it was found that 1.0 M NH 4 HCO 3 (FO‐MFC‐A) and 0.68 M NaCl (FO‐MFC‐B) had similar water fluxes of 6.04 to 3.39 LMH and 6.25 to 3.54 LMH, respectively. The reverse salt flux from the draw decreased the feed solution resistance for both draw solutes, but the FO‐MFC‐A system (0.32 W m −2 ) had a higher maximum power density than the FO‐MFC‐B system (0.26 W m −2 ). The current density for the FO‐MFC‐B system increased due to continuous solution resistance decrease, whereas it remained constant for the FO‐MFC‐A. The difference in Coulombic efficiencies (32.8% vs. 25.6%) but similar Coulombic recoveries (10.2% vs. 11.4%) between the FO‐MFC‐A and FO‐MFC‐B systems suggested that the FO‐MFC‐A might have the inhibited microbial activity by high ammonium/ammonia. The FO‐MFC‐A system had the lower energy consumption for nutrient removal (2.01 kWh kg −1 NH 4 + ‐N) and recovery (8.87 kWh kg −1 NH 4 + ‐N). These results have shown that NH 4 HCO 3 as a draw solute can have advantages of higher power density, higher Coulombic efficiency, and recoverability for draw regeneration, but its potential inhibition on microbial activity must also be considered. Practitioner Points Forward osmosis can be connected to microbial fuel cells for wastewater treatment. Water recovery by forward osmosis can greatly reduce the wastewater volume to microbial fuel cells. Ammonium draw solutes can result in lower volumetric energy consumption. Ammonia inhabitation of anode microbes will decrease organic removal.

Marcelinus Christwardana, Athanasia Amanda Septevani, Linda Aliffia Yoshi

International Journal of Renewable Energy Development • 2022

Photosynthesis is a technique for converting light energy into chemical energy that is both efficient and sustainable. Chlorophyll in energy-transducing photosynthetic organisms is unique because of their distinctive structure and composition. In photo-bioelectrochemical research, the chlorophyll's quantum trapping efficiency is attractive. Chlorophyll from Spirulina platensis is demonstrated to communicate directly with TiO2-modified Indium Thin Oxide (ITO) to generate electricity without the use of any mediator. TiO2-modified ITO with a chlorophyll concentration of 100 % generated the greatest power density and photocurrent of approximately 178.15 mW/m2 and 596.92 mA/m2 from water oxidation under light among all the other materials. While the sensitivity with light was 0.885 mA/m2.lux, and Jmax value was 1085 mA/m2. Furthermore, the power and photocurrent density as a function of chlorophyll content are studied. The polarizability and Van der Waals interaction of TiO2 and chlorophyll are crucial in enhancing electron transport in photo-bioelectrochemical systems. As a result, this anode structure has the potential to be improved and used to generate even more energy.

Leonardo Iannucci, Sabrina Grassini, Emma Angelini et al.

ECS Meeting Abstracts • 2018

Biofilms are able to change the electrochemical characteristics of passivable metals, creating anodic and cathodic areas and inducing electroactive effects that can directly influence the corrosion rate of the material in a specific environment. This kind of process is referred to as Microbial Influenced Corrosion (MIC), and, even if its mechanisms have been widely studied in literature, it remains a problem largely underestimated and difficult to prevent. A huge number of bacteria are generally involved in MIC process and one of the difficulties of carrying out laboratory tests is to reproduce this great variety. The technique employed in this study aims at overcoming these issues using a Microbial Fuel Cell (MFC) as environment to test the microbial corrosion behavior of metallic samples. In a MFC, fuel is typically composed of the organic substance dissolved in the solution that fills the anodic half-cell. Bacterial populations, inoculated in the anodic solution, build up an electroactive biofilm on the anode that catalyzes the fuel oxidation. In traditional fuel cells the anodic half-cell is separated from the cathodic one by an electrolytic membrane. In more simple MFC air-breathing systems, the biofilm growing on the cathode both consumes the oxygen diffusing through the pores, thereby guaranteeing anaerobic conditions to the anode, and catalyzes the oxygen reduction. The redox mechanisms of electroactive bacterial occurring on the anode and cathode in a MFC are similar to those involved in microbial corrosion. Therefore laboratory studies on electrophilic bacteria acting on microbial fuel cell electrodes, offer the possibility to study in well-defined anodic and cathodic regions, the mechanisms responsible for microbiological corrosion. This study, in particular, has been carried out in order to characterize the electrochemical behavior of Ag-doped hybrid coatings deposited on stainless steel. The hybrid coatings are based on epoxy resin formulations where the silver nanoparticles are produced in-situ with a bottom-up approach: the silver precursor undergoes a photoreduction reaction during the UV-curing process and leads to a microstructure with nanoparticles dispersed inside the polymeric matrix. The sample under study is inserted in the chamber of the fuel cell and connected to the two electrodes in order to be able to monitor and analyze the variation in time of the current flowing between each one of the three system nodes affected by the same bacteria pool. Both coated and uncoated stainless steel samples have been immersed in the MFC anodic chamber containing wastewater inoculated with swine manure and acetate (as fuel). The performance and growth of bacterial biofilm on the coated samples, in anaerobic conditions, have been investigated by means of anodic and cathodic polarization and electrochemical impedance spectroscopy (EIS). Eventually, the coatings and the biofilms have been morphologically characterized by means of field emission scanning electron microscopy.

Agnieszka Stróż, Thomas Luxbacher, Karolina Dudek et al.

Materials • 2023

Surface charge and in vitro corrosion resistance are some of the key parameters characterizing biomaterials in the interaction of the implant with the biological environment. Hence, this work investigates the in vitro bioelectrochemical behavior of newly developed oxide nanotubes (ONTs) layers of second-generation (2G) on a Ti–13Zr–13Nb alloy. The 2G ONTs were produced by anodization in 1 M (NH4)2SO4 solution with 2 wt.% of NH4F. The physical and chemical properties of the obtained bamboo-inspired 2G ONTs were characterized using scanning electron microscopy with field emission and energy dispersive spectroscopy. Zeta potential measurements for the examined materials were carried out using an electrokinetic analyzer in aqueous electrolytes of potassium chloride, phosphate-buffered saline and artificial blood. It was found that the electrolyte type and the ionic strength affect the bioelectrochemical properties of 2G ONTs layers. Open circuit potential and anodic polarization curve results proved the influence of anodizing on the improvement of in vitro corrosion resistance of the Ti–13Zr–13Nb alloy in PBS solution. The anodizing conditions used can be proposed for the production of long-term implants, which are not susceptible to pitting corrosion up to 9.4 V.

Pierangela Cristiani, Andrea Goglio, Stefania Marzorati et al.

Frontiers in Energy Research • 2020

Research in the field of bioelectrochemical systems is addressing the need to improve components and reduce their costs in the perspective of their large-scale application. In this view, innovative solid separators of electrodes, made of biochar and terracotta, are investigated. Biochar-based composites are produced from giant cane ( Arundo Donax L .). Two different types of composite are used in this experiment: composite A, produced by pyrolysis of crushed chipping of A.donax L . mixed clay; and composite B, produced by pyrolysis of already-pyrolyzed giant cane (biochar) mixed with clay. Electrical resistivity, electrical capacity, porosity, water retention, and water leaching of the two composites types (A and B) with 1, 5, 10, 15, 20, and 30 mass percentages of carbon (w/w) are characterized and compared. Less than 1 kΩ cm of electrical resistance is obtained for composite A with a carbon content greater than 10%, while physical and electrical performances of composite B do not significantly change. SEM micrographs and 3D microcomputed tomography of different composite materials are provided, demonstrating a different matrix structure of carbon in the terracotta matrix. The possibility of suitably decreasing electric resistance and increasing water retention/leaching of composite A opens the way for a new class of resistive materials that can be simultaneously used as electrolytic separators and as external electric circuits, allowing a compact microbial fuel cell design. A proof of concept of such an MFC design was provided for different tested composites. Although all the anolytes become anaerobic, only the MFCs equipped with the composite A30% were able to produce power, reaching the maximum power peak in correspondence to resistance of about 1 kΩ. The low, but significant, produced power (about 40 mW m −2 , cathode area) confirm that the proposed solution is particularly suitable for nutrient recovery and environment pollution bioremediation, where energy harvesting is not requested.

Jean-Marie Fontmorin, Junxian Hou, Ian Head et al.

ECS Meeting Abstracts • 2018

The majority of studies focusing on bioelectrochemical systems (BES) report the utilization of carbon-based electrodes. However, in order to overcome the limitations related to the scale-up of Microbial Fuel Cells (MFC) and Microbial Electro Synthesis (MES) cells technologies, the utilization of metal-based electrodes need to be considered due to their conductivity, cost and robustness. Stainless steel fiber felts (SSFF) as bioanode material for BES applications was investigated in this study. The unmodified SSFF was tested alongside with electrodes modified with reduced graphene oxide (rGO), magnetite nanoparticles (Fe3O4), manganese oxide (MnO 2 ) and flame-oxidation (FO). The performance of the metal-based electrodes as bioanodes were investigated in half-cells in terms of stability and current densities. In addition, the impact of the capacitance of the abiotic electrode materials on the performance of the bioanodes and MFCs was evaluated (Fig. a), especially to assess how these materials can increase the energy harvested compared to non-capacitive bioanodes. The results showed that the stainless steel- based electrodes studied are competitive alternatives to the carbon-based electrodes. Current densities recorded in half-cells were 1.96, 1.95 and 2.26 mA/cm 2 for FO-MnO2-SS, rGO-SS and carbon cloth, respectively. In addition, charge/discharge experiments carried out with the bioanodes developed (Fig. c) showed that the modified SSFF electrodes allow the storage of electrical charge from the biofilm to the capacitive layers of the electrodes when cells are left at open circuit potential (OCP). These results demonstrate the potential of these materials for energy generation and storage applications from waste in BES. Figure 1

Mina Memarpoor-Yazdi, Sara Haghighatian, Mohammad Mahdi Doroodmand et al.

Scientific Reports • 2020

Abstract In this study, we employed an electrochemical (potentiometric) method to enumerate magnetotactic bacteria (MTB) during its coupling with iodometric titration to obtain a selective, precise and rapid counting system. Oxygen was considered as an important factor for the orientation and movement of MTB towards the magnet-modified indicator electrode. In the direct potentiometry, a linear correlation was detected between potentiometric response and dissolved oxygen (DO) concentrations. By the increase of the DO concentration, potential difference would increase in the range of 4.0 to 20.0 parts per million (ppm) at different pressure conditions. The reliability of the O 2 bio-sensing feature provides a selective MTB-based cell enumeration methodology based on indirect potentiometric titration. Furthermore, a five-minute H 2 -purging resulted in an increase of potentiometric response sensitivity arising from the decrease in DO concentration of the electrolyte solution. Results were also investigated by zeta potential difference, which show the effect of charge density of MTB in presence of DO. Zeta potential was increased proportionally by addition of the MTB population. Regarding the reliability of the suggested method, data obtained by the designed system showed no statistical difference from those obtained by the most common procedure in microbiology for enumeration of bacteria, known as colony forming unit (CFU) method.

Alejandro Chamizo-Ampudia, Raúl. M. Alonso, Luisa Ariza-Carmona et al.

Bioengineering • 2025

The growing demand for sustainable bioplastics has driven research toward more efficient and cost-effective methods of producing polyhydroxyalkanoates (PHAs). Among the emerging strategies, bioelectrochemical technologies have been identified as a promising approach to enhance PHA production by supplying electrons to microorganisms either directly or indirectly. This review provides an overview of recent advancements in bioelectrochemical PHA synthesis, highlighting the advantages of this method, including increased production rates, the ability to utilize a wide range of substrates (including industrial and agricultural waste), and the potential for process integration with existing systems. Various bioelectrochemical systems (BES), electrode materials, and microbial strategies used for PHA biosynthesis are discussed, with a focus on the roles of electrode potentials and microbial electron transfer mechanisms in improving the polymer yield. The integration of BES into PHA production processes has been shown to reduce costs, enhance productivity, and support the use of renewable carbon sources. However, challenges remain, such as optimizing reactor design, scaling up processes, and improving the electron transfer efficiency. This review emphasizes the advancement of bioelectrochemical technologies combined with the use of agro-industrial waste as a carbon source, aiming to maximize the efficiency and sustainability of PHA production for large-scale industrial applications.

Serge Cosnier, Dan Shan

ECS Meeting Abstracts • 2020

For four decades, the development of biointerfaces has been the subject of increasing research efforts in the field of analytical chemistry and energy conversion. In particular, the functionalization of electrodes by biomaterials based on electrogenerated polymers and / or carbon nanotubes, is widely used for the design of biosensors and biofuel cells. Nanotube deposits were successfully functionalized by electropolymerization or π−π stacking interactions with pyrene derivatives exhibiting both affinity or covalent binding interactions towards redox molecules or proteins. Some new approaches for developing nanostructured biomaterials based on functionalized tungsten disulfide nanotubes and self-supporting film of carbon nanotubes (buckypapers) will be illustrated with enzymes as biosensing element [1]. In particular, WS 2 nanotubes functionalized with carboxylic acid functions were used for the tyrosinase immobilization in order to form an amperometric biosensor towards catechol and dopamine. Moreover, heteropolyoxometalates (C 4 H 10 N) 6 [P 2 Mo 18 O 62 ] and (C 6 H 8 NO) 4 [H 2 P 2 W 18 O 62 ] were immobilized within carbon nanotube matrix and used as mediators for the electron transfer with FAD dependent glucose dehydrogenase [2]. The glucose detection was performed with a sensitivity of 198 mAmolL -1 cm -2 , and a good reproducibility. A new generation of flexible buckypaper electrodes was produced by using linear polynorbornene polymers containing multiple pyrene groups as crosslinker [3]. In addition, the use of bifunctionalized polymers (pyrene and NHS groups) leads to robust buckypapers with the covalent binding of redox groups or enzymes [4]. We have been also interested in the development and characterization of glyconanoparticles (vesicles, micelle aggregates) obtained from the self-assembly of block copolymers composed of polystyrene as a hydrophobic tail and cyclodextrin as a hydrophilic part. These glyconanoparticles, which are stable in suspension in aqueous media, have an outer layer composed of cyclodextrin which allows a post-functionalization of the nanoparticle by hydrophobic molecules through host-guest interactions. These nanoparticles are thus a versatile platform for fixing a wide range of redox mediators. Two types of redox nanoparticles in solution for the electrical connection of enzymes have been developed: nanoparticle modified by 9,10-phenanthrenequinone and nanoparticle modified by ABTS modified by two pyrene groups. This innovative approach will be applied to the electrical wiring of enzymes in solution for the elaboration of solubilized enzymatic fuel cell [5,6]. Acknowledgements The author wishes to acknowledge the support from the Sino-French international research network GDRI 0876 “New nanostructured materials and biomaterials for renewable electrical energy sources” for providing facilities. This work is partly supported by the French National Research Agency (ANR-18-CE09-0022-01). [1] References 1. J. Gross, M. Holzinger, S. Cosnier. Energy Environ.Sci ., 11 , 1670-1687 (2018) 2. Boussema, A. J. Gross, F. Hmida, B. Ayed, H. Majdoub, S. Cosnier, A. Maaref, M. Holzinger. Biosens. Bioelectron ., 109, 20-26 (2018) 3. Chen, L. Yin, J. Lv, A. J. Gross, M. Le, N. G. Gutierrez, Y. Li, I. Jeerapan, F. Giroud, A. Berezovska, R. K. O’Reilly, S. Xu, S. Cosnier, J. Wang. Adv. Funct. Mater., in press. 4. Fritea, A. Gross, K. Gorgy, R. O’Reilly, A. Le Goff, S. Cosnier. J. Mat. Chem. A, 7 1447-1450 (2019) 5. J. Gross, X. Chen, F. Giroud, C. Travelet, R. Borsali, S. Cosnier, J. Am. Chem. Soc ., 139 , 16076-16079 (2017) 6. L. Hammond, A. J. Gross, F. Giroud, C. Travelet, R. Borsali, S. Cosnier. ACS Energy Lett., 4 ,142-148 (2019) [1] Tel 33 456 520 810; Fax 33 456 520 803; email: Serge.Cosnier@univ-grenoble-alpes.fr

Lorenzo Cristiani, Jacopo Ferretti, Mauro Majone et al.

Membranes • 2022

Bioelectrochemical systems are emerging technologies for the reduction in CO2 in fuels and chemicals, in which anaerobic chemoautotrophic microorganisms such as methanogens and acetogens are typically used as biocatalysts. The anaerobic digestion digestate represents an abundant source of methanogens and acetogens microorganisms. In a mixed culture environment, methanogen’s inhibition is necessary to avoid acetate consumption by the presence of acetoclastic methanogens. In this study, a methanogenesis inhibition approach based on the thermal treatment of mixed cultures was adopted and evaluated in terms of acetate production under different tests consisting of hydrogenophilic and bioelectrochemical experiments. Batch experiments were carried out under hydrogenophilic and bioelectrochemical conditions, demonstrating the effectiveness of the thermal treatment and showing a 30 times higher acetate production with respect to the raw anaerobic digestate. Moreover, a continuous flow bioelectrochemical reactor equipped with an anion exchange membrane (AEM) successfully overcomes the methanogens reactivation, allowing for a continuous acetate production. The AEM membrane guaranteed the migration of the acetate from the biological compartment and its concentration in the abiotic chamber avoiding its consumption by acetoclastic methanogenesis. The system allowed an acetate concentration of 1745 ± 30 mg/L in the abiotic chamber, nearly five times the concentration measured in the cathodic chamber.