J. Annie Modestra, S. Venkata Mohan

Bioresource Technology • 2019

Na Chu, Donglin Wang, Houfeng Wang et al.

Engineering • 2021

The development of microbial electrosynthesis (MES) for renewable electricity-driven bioutilization of CO2 has recently attracted considerable interest due to its ability to synthesize chemicals with the transition towards a circular carbon economy. However, the increase of acetate production and the decrease of energy consumption of MES using an advanced reactor design have received less attention. In this study, the total acetate production rate using novel flow-electrode MES reactors ((16 ± 1) g·m−2·d−1) was double that using reactors without powder activated carbon (PAC) amendment ((8 ± 3) g·m−2·d−1). The flow-electrode MES reactors had a Coulombic efficiency of 43.5% ± 3.1%, an energy consumption of (0.020 ± 0.005) kW·h·g−1, and an energy efficiency of 18.7% ± 1.3% during acetate production. The flow-electrode with PAC amendment could decrease the net water flux and charge transfer resistance, while had little impact on the cell voltage, rheological behavior, and acetate adsorption. In the flow-electrode MES reactors, the expression of genes involving in energy production and conversion were increased, and the increase of acetate production was found correlated with the increased abundance of Acetobacterium. The Wood–Ljungdahl pathway (WLP) and reductive citric acid cycle (rTCA) were found to be the pathways responsible for carbon fixation. The concentrations of acetate in the stacked flow-electrode MES reached 7.0 g·L−1. This study presents a new approach for the construction of scalable MES reactors with high-performance chemical generation and CO2 utilization.

Xiaobo Zhu, Joshua Jack, Aaron Leininger et al.

Resources Conservation and Recycling • 2022

Fuád Ameén, Wafa A. Alshehri, Saleh Al Nadhari

ACS Sustainable Chemistry & Engineering • 2019

Microbial electrosynthesis (MES) is a biocathode driven production of value added platform chemicals from carbon dioxide (CO2), which is regarded as a sustainable carbon mitigation approach. In this technique, electrons are supplied from external sources and subsequently utilized by the microorganisms present in the MES cathode for converting CO2 into useful chemicals (i.e. acetic acids, butyric acid, propanol, ethanol, etc.). However, the performance of MES severely depends on the formation of an electroactive biofilm with the ability of paramount charge discharging properties. In the present work, we have investigated the influence of electroactive biofilm formation on the performance of acetic acid production in an anaerobic sludge driven MES system. The formation electroactive biofilm on the MES biocathode was characterized using different electrochemical techniques, such as chronoamperometry, linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy, and correlated with the performance of acetic acid production. The electrochemical results demonstrated that the formation of mature electroactive biofilms on biocathodes enabled a maximum 36.66 mmol/L of acetic acids. Furthermore, the influence of different applied potentials on electroactive biofilm formation as well as acetic acid production was investigated, and it was observed that the applied potential of −0.68 V achieved maximum reducing current and acetic acid production together with maximum CO2 consumption. The phylogenetic analysis of cathode biofilm revealed that Burkholderiales sp., Sulfurospirillum sp., Acetoanaerobium sp., and Lysinibacillus sp. were the predominant microbial genera associated with the electrosynthetic reactions in MES systems. The results of the present study suggest that the formation of an electroactive biofilm enriched with electrosynthetic genera is beneficial to avail maximum performance in MES systems.

Weifeng Kong, Liping Huang, Xie Quan et al.

Applied Catalysis B: Environmental • 2020

Bin Bian, Le Shi, Krishna P. Katuri et al.

Applied Energy • 2020

Marzieh Omidi, Mehrdad Mashkour, Jayanta Kumar Biswas et al.

Topics in Catalysis • 2021

Hou-Yun Yang, Nannan Hou, Yixuan Wang et al.

The Science of The Total Environment • 2021

Bin Bian, Jiajie Xu, Krishna P. Katuri et al.

Bioresource Technology • 2020

Suman Bajracharya, Adolf Krige, Λεωνίδας Μάτσακας et al.

Chemosphere • 2021

High-rate production of acetate and other value-added products from the reduction of CO 2 in microbial electrosynthesis (MES) using acetogens can be achieved with high reducing power where H 2 appears as a key electron mediator. H 2 evolution using metal cathodes can enhance the availability of H 2 to support high-rate microbial reduction of CO 2 . Due to the low solubility of H 2 , the availability of H 2 remains limited to the bacteria. In this study, we investigated the performances of Sporomusa ovata for CO 2 reduction when dual cathodes were used together in an MES, one was regular carbon cathode, and the other was a titanium mesh that allows higher hydrogen evolution. The dual cathode configuration was investigated in two sets of MES, one set had the usual S. ovata inoculated graphite rod, and another set had a synthetic biofilm-imprinted carbon cloth. Additionally, the headspace gas in MES was recirculated to increase the H 2 availability to the bacteria in suspension. High-rate CO 2 reduction was observed at -0.9 V vs Ag/AgCl with dual cathode configuration as compared to single cathodes. High titers of acetate (up to ∼11 g/L) with maximum instantaneous rates of 0.68-0.7 g/L/d at -0.9 V vs Ag/AgCl were observed, which are higher than the production rates reported in the literatures for S. ovata using MES with surface modified cathodes. A high H 2 availability supported the high-rate acetate production from CO 2 with diminished electricity input.

Anthony J. Abel, Douglas S. Clark

ChemSusChem • 2020

Mediated microbial electrosynthesis (MES) represents a promising strategy for the capture and conversion of CO 2 into carbon-based products. We describe the development and application of a comprehensive multiphysics model to analyze a formate-mediated MES reactor. The model shows that this system can achieve a biomass productivity of ∼1.7 g L -1 h -1 but is limited by a competitive trade-off between O 2 gas/liquid mass transfer and CO 2 transport to the cathode. Synthetic metabolic strategies are evaluated for formatotrophic growth, which can enable an energy efficiency of ∼21 %, a 30 % improvement over the Calvin cycle. However, carbon utilization efficiency is only ∼10 % in the best cases due to a futile CO 2 cycle, so gas recycling will be necessary for greater efficiency. Finally, separating electrochemical and microbial processes into separate reactors enables a higher biomass productivity of ∼2.4 g L -1 h -1 . The mediated MES model and analysis presented here can guide process design for conversion of CO 2 into renewable chemical feedstocks.

Mélida del Pilar Anzola-Rojas, Marcelo Zaiat, Ernesto Rafael González et al.

Process Biochemistry • 2020

Rusen Zou, Aliyeh Hasanzadeh, Alireza Khataee et al.

iScience • 2021

Microbial electrosynthesis system (MES) has recently been shown to be a promising alternative way for realizing in situ and energy-saving synthesis of hydrogen peroxide (H 2 O 2 ). Although promising, the scaling-up feasibility of such a process is rarely reported. In this study, a 20-L up-scaled two-chamber MES reactor was developed and investigated for in situ and efficient H 2 O 2 electrosynthesis. Maximum H 2 O 2 production rate of 10.82 mg L -1 h -1 and cumulative H 2 O 2 concentration of 454.44 mg L -1 within 42 h were obtained with an input voltage of 0.6 V, cathodic aeration velocity of 0.045 mL min -1 mL -1 , 50 mM Na 2 SO 4 , and initial pH 3. The electrical energy consumption regarding direct input voltage was only 0.239 kWh kg -1 H 2 O 2 , which was further much lower compared with laboratory-scale systems. The obtained results suggested that the future industrialization of MES technology for in situ synthesis of H 2 O 2 and further application in environmental remediation have broad prospects.

Chaeho Im, Kaspar Valgepea, Oskar Modin et al.

Bioresource Technology Reports • 2022

Microbial electrosynthesis enables the production of value-added chemicals from CO2 and electrons provided by an electrode. Clostridium ljungdahlii is an electroactive acetogen that potentially could be used in microbial electrosynthesis systems. However, the optimal operational parameters for microbial electrosynthesis using C. ljungdahlii are not known. Here, we explored the effects of yeast extract, pH, and cathode potential. A low initial pH increased the rate of acetate production from CO2 and H2 in serum bottle cultures. When cultivated in bioelectrochemical systems, the optimal coulombic efficiency (i.e. close to 100 %) was observed at a cathode potential between −0.8 V and −1.0 V, while the highest productivity was reached at −1.0 V. Addition of yeast extract to the medium was needed to ensure reproducible results. Using cyclic voltammetry, we detected hydrogen-mediated extracellular electron transfer of C. ljungdahlii during growth on CO2 in a bioelectrochemical system. These results show that operational parameters should be chosen carefully to maximise the efficiency of microbial electrosynthesis.

José Gavilanes, C. Nagendranatha Reddy, Booki Min

Energy & Fuels • 2019

The efficiency and characteristics of conversion of volatile fatty acids (VFAs) into alcohols by a microbial electrosynthesis (MES) process were significantly influenced by the initial organic loading concentration and operational period. The acetate and butyrate concentrations ranged from 2 to 8 g-COD/L, and alcohol and other product formations were determined over a 5 day operation. The highest yield of 0.218 g-CODAlcohol/g-CODVFAs was obtained for 4 g-COD/L after a 1 day operation. A gradual decrease over time in alcohol recovery was noticed for all VFA concentrations due to methane generation under elevated pH conditions. At the end of the operation, a higher bioalcohol yield was achieved at a relatively lower VFA concentration of 2 g-COD/L. A large fraction of initial VFAs remained unchanged without bioenergy production from higher substrate concentrations (6 and 8 g-COD/L). The energy recovery of total products (alcohols and methane) based on the input power was less than about 24% at the end of the operation. This study suggests that the optimized loading of VFA and low-pH conditions are essentially required to increase the overall performance of the MES system for alcohol production.

Na Chu, Qinjun Liang, Wei Zhang et al.

ACS Sustainable Chemistry & Engineering • 2020

Waste C1 gases as alternatives to pure CO2 can potentially facilitate the practical application of microbial electrosynthesis (MES) for chemical production and further decrease the total cost. This work evaluated the impact of the CO fraction on MES of C2–C6 carboxylates. Using the CO/CO2 mixture as the substrate in MES favors simultaneous acetogenesis, solventogenesis, and chain elongation. The test of CO-50% achieved the best performance of production of C4 and C6 carboxylates, of which the specificity based on the electron recovery was 43.11 ± 1.31% for acetate, 34.11 ± 0.11% for butyrate, and 15.41 ± 1.48% for caproate, while the lag phase was 32 days for butyrate and 44 days for caproate. However, the specificity observed with pure CO2 (CO-0% test) was 85.37 ± 3.24% for acetate, 10.68 ± 2.54% for butyrate, and 0% for caproate. The increase of CO fraction decreased the electron recovery to methane. Microbial diversity analysis demonstrated that the elevated CO fraction increased the relative abundance of Acetobacterium as well as Clostridium. This study proved that waste C1 gases as alternatives to pure CO2 could stimulate the generation of C4 and C6 carboxylates in MES.

Hui Wang, Yang Liu, Hongxia Du et al.

Biochemical Engineering Journal • 2021

Khurram Tahir, Waheed Miran, Jiseon Jang et al.

Environmental Research • 2021

Tian‐shun Song, Lin Fu, Ningkun Wan et al.

Journal of CO2 Utilization • 2020

Yong Jiang, Na Chu, Wei Zhang et al.

Water Research • 2019

Zhuo Li, Qian Fu, Hajime Kobayashi et al.

International Journal of Hydrogen Energy • 2019

Oriol Cabau-Peinado, Adrie J. J. Straathof, Ludovic Jourdin

Frontiers in Microbiology • 2021

Up to now, computational modeling of microbial electrosynthesis (MES) has been underexplored, but is necessary to achieve breakthrough understanding of the process-limiting steps. Here, a general framework for modeling microbial kinetics in a MES reactor is presented. A thermodynamic approach is used to link microbial metabolism to the electrochemical reduction of an intracellular mediator, allowing to predict cellular growth and current consumption. The model accounts for CO 2 reduction to acetate, and further elongation to n-butyrate and n-caproate. Simulation results were compared with experimental data obtained from different sources and proved the model is able to successfully describe microbial kinetics (growth, chain elongation, and product inhibition) and reactor performance (current density, organics titer). The capacity of the model to simulate different system configurations is also shown. Model results suggest CO 2 dissolved concentration might be limiting existing MES systems, and highlight the importance of the delivery method utilized to supply it. Simulation results also indicate that for biofilm-driven reactors, continuous mode significantly enhances microbial growth and might allow denser biofilms to be formed and higher current densities to be achieved.

Gaoyuan Shang, Kai Cui, Wenfang Cai et al.

Chemical Engineering Journal • 2022

Carla Flores-Rodriguez, Booki Min

Bioresource Technology • 2019

Sovik Das, Pritha Chatterjee, Makarand M. Ghangrekar

Water Science & Technology • 2018

Electrosynthesis of multi-carbon compounds from the carbon dioxide present in biogas is a nascent approach towards purification of biogas. Microbial electrosynthesis (MES) cells, fabricated using different electrode materials, were operated using different electrolytes and mixed anaerobic culture as biocatalysts in the cathodic chamber under an applied cathode potential of -0.7 V vs standard hydrogen electrode (SHE). The rate of production of acetate, isobutyrate, propionate and 2-piperidinone from reduction of CO 2 in the cathodic chamber of the MES was 0.81 mM/day, 0.63 mM/day, 0.44 mM/day and 0.53 mM/day, respectively. As methane was also present in the biogas, methyl derivatives of these acids were also found in traces in catholyte. It was observed that the use of nickel foam as an anode, 1 M NiSO 4 solution as anolyte, graphite felt as a cathode, phosphate buffer solution as catholyte at a pH of 5.2 proved to be the best possible combination for MES for this study to get enhanced product yield at higher energy efficiency.

Santiago T. Boto, Bettina Bardl, Falk Harnisch et al.

Green Chemistry • 2023

Microbial electrosynthesis (MES) is a very promising technology addressing the challenge of carbon dioxide recycling into organic compounds, which might serve as building blocks for the (bio)chemical industry. However, poor process control and understanding of fundamental aspects such as the microbial extracellular electron transfer (EET) currently limit further developments. In the model acetogen Clostridium ljungdahlii , both direct and indirect electron consumption via hydrogen have been proposed. However, without clarification neither targeted development of the microbial catalyst nor process engineering of MES are possible. In this study, cathodic hydrogen is demonstrated to be the dominating electron source for C. ljungdahlii at electroautotrophic MES allowing for superior growth and biosynthesis, compared to previously reported MES using pure cultures. Hydrogen availability distinctly controlled an either planktonic- or biofilm-dominated lifestyle of C. ljungdahlii . The most robust operation yielded higher planktonic cell densities in a hydrogen mediated process, which demonstrated the uncoupling of growth and biofilm formation. This coincided with an increase of metabolic activity, acetate titers, and production rates (up to 6.06 g L -1 at 0.11 g L -1 d -1 ). For the first time, MES using C. ljungdahlii was also revealed to deliver other products than acetate in significant amounts: here up to 0.39 g L -1 glycine or 0.14 g L -1 ethanolamine. Hence, a deeper comprehension of the electrophysiology of C. ljungdahlii was shown to be key for designing and improving bioprocess strategies in MES research.

Zhenghong Cai, Liping Huang, Xie Quan et al.

Applied Catalysis B: Environmental • 2020

Tian‐shun Song, Tao Li, Ran Tao et al.

The Science of The Total Environment • 2021

Gunda Mohanakrishna, Karolien Vanbroekhoven, Deepak Pant

Reaction Chemistry & Engineering • 2018

The reduction of carbon dioxide (CO 2 ) released from industry can help to reduce the emissions of greenhouse gases (GHGs) to the atmosphere while at the same time producing value-added chemicals and contributing to carbon fixation.

Mengmeng Cui, Huarong Nie, Tao Zhang et al.

Sustainable Energy & Fuels • 2017

The production of hierarchical hybrid conductive materials that are mesoporous, with pores spanning from sub-microns to microns in size, is important for large-area electrode applications.

Gahyun Baek, Ruggero Rossi, Pascal E. Saikaly et al.

Water Research • 2022

Xiaohu Li, İrini Angelidaki, Yifeng Zhang

Journal of Power Sources • 2016

Tian‐shun Song, Kangqing Fei, Hongkun Zhang et al.

Journal of Chemical Technology & Biotechnology • 2017

Abstract BACKGROUND Microbial electrosynthesis (MES) is a biocathode‐driven process, producing high‐value chemicals, from CO 2 . However, the low efficiency of the biocathode hinders the MES process efficiency significantly. RESULTS A novel 3D graphene–nickel foam (G‐NF) cathode has been fabricated, by hydrothermal approach for the improvement of microbially‐catalyzed reduction at the MES cathode. An increase of 1.8 times in the volumetric acetate production rate was obtained, compared with the untreated nickel foam. In MES with G‐NF, a volumetric acetate production rate of 3.11 mmol L ‐1 day ‐1 has been achieved; 70% of the electrons consumed were recovered and the final acetate concentration reached 5.46 g L ‐1 within 28 days. CONCLUSION The hierarchical porous G‐NF cathode improved bacterial colonization and the efficiency of mass, nutrients and protons transfer due to its 3D composition; the graphene coating considerably increased the effective surface area for microbial adhesion, as well as the electron transfer rate of biofilm in the MES. This study attempted to improve the efficiency of the biocathode, and provides a promising large electrode for large‐scale MES devices. © 2017 Society of Chemical Industry

Adolf Krige, Ulrika Rova, Paul Christakopoulos

Journal of environmental chemical engineering • 2021

Microbial Electrosynthesis (MES) is emerging as a promising technology for the decarbonization of the economy. The use of CO2 as a feedstock, i.e. through carbon capture and utilization, can create attractive business opportunities for the production of third generation biofuels. Achieving highly efficient electron transfer from the cathode to microbes is one of the main challenges hindering the development of MES reactors. It is, therefore, essential to improve biofilm growth for enhanced electron-transfer during bioconversion. In this study we show the first use of 3D bio-printing for microbial electrosynthesis systems, creating a “synthetic biofilm”, containing Sporomusa ovata. The synthetic biofilm greatly improves the acetate production rate while drastically decreasing start-up time. Using H-cell reactors, poised at −0.8 V vs Ag/AgCl, with a synthetic biofilm printed on a carbon cloth electrode, an average acetate productivity of 47±5.1 g day−1 m−2 (0.31±0.55 g L−1 day−1) with a maximum productivity of 104 g day1 m−2 (0.68 g L−1⋅day−1) was achieved. This is an order of magnitude higher than typical S. ovata production rates, and 2–3 fold higher than reactors using specialized cathodes. Start-up of MES reactors typically require days, whereas a high production rate was achieved almost directly after the start-up (±40 h) using the synthetic biofilm. Cyclic voltammetry data showed H2 formation occurred at much higher potentials than in the control reactors, (approx. −550 mV vs. −950 mV for controls). Imaging showed that the synthetic biofilm allowed for dense growth of S. ovata cells at the cathode, increasing electron transfer efficiency and potentially improving the bio-catalyzation of H2.

Sovik Das, Indrasis Das, Makarand M. Ghangrekar

Journal of environmental chemical engineering • 2020

Zhuangzhuang Liu, Xiaoyuan Xue, Wenfang Cai et al.

Biochemical Engineering Journal • 2022

Xiaohu Li, İrini Angelidaki, Yifeng Zhang

Water Research • 2018

Khurram Tahir, Waheed Miran, Jiseon Jang et al.

The Science of The Total Environment • 2021

Abraham Gomez Vidales, Sasha Omanovic, B. Tartakovsky

Bioresource Technology Reports • 2019

Abdul Hakeem Anwer, Mohd Shoeb, Fouzia Mashkoor et al.

Applied Catalysis B: Environmental • 2023