Spent Tea Leaves and Coffee Grounds as Potential Biocathode for Improved Microbial Electrosynthesis Performance

Tahir, Khurram; Ali, Abdul Samee; Kim, Bolam; Lim, Youngsu; Lee, Dae Sung

doi:https://doi.org/10.1155/2023/1318365

International Journal of Energy Research

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Abstract Introduction Materials Discussion Conclusion Data Availability Conflicts of Interest Acknowledgments Supplementary Materials References Copyright Related Articles

Research Article | Open Access

Volume 2023 | Article ID 1318365 | https://doi.org/10.1155/2023/1318365

Spent Tea Leaves and Coffee Grounds as Potential Biocathode for Improved Microbial Electrosynthesis Performance

Khurram Tahir,¹Abdul Samee Ali,¹Bolam Kim,¹Youngsu Lim,¹and Dae Sung Lee¹

Academic Editor: Rafael M. Santos

Received02 Dec 2022

Revised08 Feb 2023

Accepted11 Feb 2023

Published24 Feb 2023

Abstract

Microbial electrosynthesis (MES) has emerged as a sustainable energy platform capable of simultaneous wastewater treatment and valuable chemical production. The performance of MES, like other bioelectrochemical systems, largely depends on its electrode (cathode), providing the platform for microbial growth as well as electron transfer. However, most of the electrodes are expensive, and their nonrenewable characteristics, cost, and poisoning nature are major bottlenecks in MES commercialization. Thus, several efforts have been made to explore the potential of waste carbon-based electrodes to reduce carbon footprints as well as electrode manufacturing costs. In this study, the feasibility of using spent tea leaves (STL) and spent coffee grounds (SCG) as MES biocathode was tested. Different bioelectrochemical tests suggested improved MES performance with STL and SCG biocathode along with reduced electrode resistance and improved current density. A 1.5- and 2.0-fold increase in cyclic voltammetry (CV) current output was observed for SCG and STL, respectively, with substantial mediator peaks of high intensity indicating enhanced electrocatalytic activity. Enrichment of some fermentative and exoelectrogenic microbial classes such as Clostridia, Bacteroidia, and Deltaproteobacteria led to a 1.3- and 1.4-fold increase in butyrate production for SCG and STL cathode, respectively. These results demonstrate the potential of STL and SCG as MES cathode for improved energy and chemical production.

1. Introduction

Continuous exhaustion and depletion of natural energy resources combined with increased emissions of greenhouse gases such as carbon dioxide (CO₂) has been a major problem faced by mankind today [1]. To overcome this alarming situation, microbial electrosynthesis (MES) has emerged as an efficient and multifaceted technology capable of consuming CO₂ and converting it into useful chemicals such as biofuels, organic acids, and other chemicals via microbial catalysts [2]. This technology not only provides a green method of chemical synthesis, but it also reduces the carbon footprint, which makes it a competent and viable platform for sustained and simultaneous production of energy and chemical [3].

Similar to other bioelectrochemical systems, MES performance largely depends on its electrodes for microbial attachment as well as its platform for electron transfer [4, 5]. In this context, different electrode materials including carbon based electrodes decorated with nanomaterials, metals, polymers, and composites have been used [6, 7]. However, the complex and rigorous preparation processes along with the high cost hinder scaling up MESs [8]. Therefore, it is imperative to explore inexpensive, readily available, and highly efficient electrode materials. In this context, carbon-rich waste materials have become promising materials for fabricating electrodes owing to their naturally porous structure, availability, high mineral content, biocompatibility, and low cost [8]. Several electrodes prepared from carbon-rich waste materials, such as those from biochar and organic waste [9, 10], kenaf and bamboo [11], and cotton textile and chestnut shell [12], have been tested. All these materials exhibit improved bioelectrochemical performance in terms of biofilm formation, electrode-microbe interaction, and current density performance than conventional electrodes [13].

Among different carbon-rich waste materials, spent tea leaves (STL) and spent coffee grounds (SCG) are one of the most abundant by-products generated worldwide due to high global consumption of tea and coffee, which reached up to 6 and 10 million tons, respectively, in 2020 [14, 15]. Huge quantities of solid residues (~90%) of STL and SCG are produced during their brewing for different types of products such as canned, bottled, and instant products [14]. Continuous disposal of these waste products in open field is problematic and may increase anthropogenic gas emission and water and soil pollution owing to the toxic nature of its components, including caffeine, polyphenols, and tannins [15]. Notably, STL and SCG are potential energy sources enriched with carbon-derivatives such as alkaloids and polyphenols (STL) and organic compounds including fatty acids, hemicelluloses, lignin, cellulose, and other polysaccharides (SCG) [14, 15]. Recent studies have highlighted the potential of SCG and STL as a source of sugars [16], bioethanol [17], and biodiesel [18], and some studies have exploring the use of STL and SCG for fabricating electrodes [19–21]. In this context, STL and SCG are promising options for use in MESs to reduce the carbon footprint and energy consumption associated with electrode manufacturing. In this study, the bioelectrochemical performance and bicarbonate reduction to different volatile fatty acids (VFAs) of STL and SCG were monitored to evaluate their feasibility as MES cathodes (Figure 1). A mixed microbial culture was used instead of pure strains owing to its resilience to environmental disturbances and capacity to produce high biomass [22]. At the end of the experiment, the transformation and enrichment of relatively abundant microbes were evaluated to identify the microbial communities active on STL and SCG biocathode.

2. Materials and Method

2.1. Preparation of STL and SCG Electrode

The SCG was collected from a local coffee shop in Korea while STL was collected from a local tea brand. Both materials were washed and air dried. To assemble STL and SCG as electrodes, an empty tea bag was used. Five gram of each of STL and SCG was filled in empty tea bags (), and an empty tea bag was used as control. The anode used was carbon cloth, infused with 20 wt% Pt (Fuel Cell Earth, Wakefield, USA) with an effective area of .

2.2. MES System Assembly and Operation

A dual Plexiglas box () with 0.2 L capacity comprised the MES setup, as described in our previous studies [23, 24]. The cathode and anode chambers were separated by a proton exchange membrane PEM (Nafion® 117, DuPont Co., USA) pre-treated with 0.5 M H₂SO₄ and 3% H₂O₂. The experiment was run with three separate MES systems each installed with a different cathode (control/STL/SCG) while other experimental parameters were kept constant. For starting MES, each reactor was fed with growth media (0.18 L) and microbial culture (0.02 L) for four weeks before the start of experiment. To ensure smooth operation and microbial activity, exhausted growth media was replaced with fresh one at the end of each cycle. The experiment was carried for three cycles, each lasting for 120 h at constant temperature () and 180 rpm; 0.1 M phosphate buffer (pH 7.0) was used as the anolyte.

2.3. Electrochemical Measurements

A multichannel potentiostat comprising a three-electrode setup (wizECM-8100 Premium, Korea) was used for electrochemical measurements. In brief, cathode, anode, and saturated Ag/AgCl functioned as working, counter, and reference electrode, respectively. The chronoamperometry (CA) evaluated the current performance in a current density-time plot, with cathode poised at a fixed –800 mV vs. Ag/AgCl potential. The microbial exoelectrogenic activity was analyzed by cyclic voltammetry (CV) under a wide range of applied potential (–800 mV to +200 mV) and scan rate (1 mV/s to 200 mV/s). Fresh growth medium was added prior to CV analysis to ensure equilibrium between electrode and electrolyte. Electrochemical impedance spectroscopy (EIS) was used to measure the electrode resistance in an electrolyte solution mixture of potassium ferricyanide (5 mM) and phosphate buffer (5 mM). The electrode was poised at a fixed potential (+200 mV vs. Ag/AgCl) and evaluated under a broad frequency range of 100 kHz to 0.01 Hz.

2.4. Volatile Fatty Acid Detection and Microbial Community Analysis

VFA production was monitored by collecting samples every 24 h and subjecting them to a high-performance liquid chromatography (HPLC, Agilent 1200, USA). A refractive index detector (G1362A) and ion exchange column (Aminex HPX-87H; ) were used to analyze the samples at 60°C using 4 mM H₂SO₄ (mobile phase) under isocratic elution mode. VFAs were identified by comparing the observed peaks with available standards. The microbial communities were analyzed at the end of the experiment. Briefly, the supernatant was removed by centrifuging samples at 12,000 rpm and storing the microbial pellet for further analysis. The detailed microbial community analysis using bacterial 16S ribosomal ribonucleic acid along with the list of primers and templates (Table S1) used for the polymerase chain reaction is provided in supplementary information (available here).

3. Result and Discussion

3.1. Current Performance

The current performance was evaluated for MES cycle 1, 2, and 3 (Figures 2(a)–2(c)), each lasting 5 days with MES system poised at fixed cathodic potential of −800 mV (vs. Ag/AgCl). The negative potential enabled the electron transfer from cathode to outer cell membrane proteins/cytochromes, depicting its electrochemical activity [25]. The current output was documented every 60 s, and we noted a drop in current during MES operation, which possibly indicated exhaustion of microbial feed with time [26]. Hence, nutrient availability (supplementary data) was ensured by using fresh growth media at the start of each MES cycle. The system initiation gradually stabilized current density performance as current output increased for STL and SCG systems in subsequent MES cycles. The average current density was evaluated from 24 h of each cycle, once current became increasingly stabilized. Comparison of the average current densities revealed an increase in current output (mA/m²) from –40.6 to –48.1 (SCG) and –44.9 to –128.1 (STL) from cycle 1 to cycle 3, respectively (Figures 2(a) and 2(c)). Several studies have reported increased current output with time [27, 28]. In our study, STL showed higher current output (–128 mA) compared to SCG (–48 mA), indicating its improved bioelectrochemical performance. At the end of the third MES cycle, STL exhibited 2.4- and 2.7-fold increased current output compared to control and SCG, respectively, which was consistent with the results discussed above (Figure 2(c)). Recent studies have also reported improved current performance for STL and reported mild antimicrobial properties of SCG that could affect microbial metabolism [19, 21, 29].

(a)

(b)

(c)

3.2. Cyclic Voltammetry and Microbial Electrosynthesis of VFAs

The bioelectrochemical performance was further evaluated by CV at the end of the experiment. The electron uptake was monitored by conducting the CV analysis under multiple scan rates (1–200 mV s⁻¹) for control (Figure 3(a)), STL (Figure 3(b)), and SCG (Figure 3(c)). A considerable increase in current output (mA) was observed from −2.2 to −3.2 and−4.3 for control, SGC, and STL electrode system, respectively (Figure 3(d)). The 1.5- and 2.0-fold increase in the current output using SGC and STL electrode system, respectively (compared to control), indicated improved electron transfer. To further confirm the effect of STL and SGC on MES performance, VFA production was evaluated every 24 h using HPLC. Butyrate was observed for all MES systems (Figure 4(a)), while minimal concentration of acetate and propionate were noted (Figure 4(b)). Furthermore, butyrate production (mg/L) increased from 294, 256, 308 to 376, 473, 533 for control, STL and SCG, from first to third cycle, respectively, and the increase was significantly higher for STL (Figure 4(a)). This improved performance could be attributed to the enhanced electron utilization, which is key for improving VFA [30]. These results are consistent with the results showing enhanced current and CV output for STL.

(a)

(b)

(c)

(d)

(a)

(b)

3.3. First Derivative and EIS Analysis

The electrochemical activities of STL and SCG and the subsequent microbial electron uptake were examined by performing CV first-derivative analysis [25]. The control exhibited limited redox peaks, while the sizes/intensities of the STL and SCG peaks were visibly dominant indicating their improved electrochemical activity [31]. The STL and SCG biocathode exhibited a number of redox peaks (Figure 5(a)) such as +79 mV, −172 mV, −421 mV, −673 mV, and −800 mV (STL) and +145 mV, −207 mV, −287 mV, −446 mV −612 mV, and −713 mV (SCG), respectively. The presence of these peaks signifies the presence of different mediators assisting the electron transfer in STL and SCG [32, 33]. The redox peak of −185 mV (close to −172 mV) and−201 mV (close to −207 mV) represented by STL and SCG, respectively, could correspond to OmcA [34] species, whereas flavoproteins are likely related to the −436 mV redox potential (SCG) [35]. The potential values of −261 mV, −459 mV, and −800 mV that are close to those of our MES system have also been reported in literature with minor differences which could be attributed to system configuration, experimental conditions, microbial source, and the existence of free or biofilm-bound mediators [36–38]. Since we used a mixed microbial culture, the observed peaks could not be ascribed to any specific bacteria. Furthermore, the electrocatalytic activity was evaluated using EIS analysis in a typical three-electrode system (Figure 5(b)). The charge transfer resistance (R_ct) illustrated the charge transport efficiency and electrode/electrolyte interfacial phenomenon [39]. The circuit component parameters were evaluated across a large frequency range using an equivalent circuit of R(QR)(QR), and the equivalent circuit model fitting was performed using ZSimpWin software (AMETEK, USA) for plotting the Nyquist curve. Nyquist curves showed a lower charge transfer resistance for STL (335 Ω) and SCG (282 Ω) compared to control (1378 Ω). A lower R_ct reportedly enhances the electronic delivery, thus improving the current density performance and electrocatalytic activity toward the charge transfer [40, 41]. The EIS results supported the current density and CV, further confirming that STL and SCG improved the bioelectrochemical system performance.

(a)

(b)

3.4. Microbial Community Analysis

The microbial community and biofilm generation were evaluated for control, STL, and SCG at the end of the experiment. The microbial samples were classified at the phylum, class, and genus levels based on the results of 16S rRNA gene pyrosequencing and assigned operational taxonomic units. At the phylum level, Firmicutes, Proteobacteria, and Bacteroidetes showed the highest relative abundance for control (95%), STL (79%), and SCG (75%); however, microbial shift and transformation were evident for STL and SCG in terms of Chloroflexi, Actinobacteria, Thermotogae, and Ignavibacteriae (Figure 6(a)). These phyla comprise excellent fermenters that show better VFA production in MES [42, 43]. This was further confirmed in our study where Clostridia (54% and 43%), Bacteroidia (14% and 8%), and Deltaproteobacteria (6% and 4%), shared the highest relative abundance for STL and SCG biocathode, respectively (Figure 6(b)). The Clostridia, Bacteroidia, and Deltaproteobacteria are exoelectrogenic and fermentative bacteria which may be linked to the improved current output and VFA [44–46]. Genus level analysis indicated enrichment of Acidaminobacter, Lentimicrobium, Mesotoga, and Ignavibacterium, which can improve VFA production (Figure 6(c)) [47–49]. Moreover, the collective abundance of these microbes enriched on STL and SCG may have further favored MES performance as evident from improved current density and VFA results of STL and SCG.

(a)

(b)

(c)

4. Conclusion

The SCG and STL biocathodes exhibited improved bioelectrochemical performance and current density with 1.5- and 2.0-fold increase in CV current compared to that in control. Both MESs exhibited lower electrode resistance and redox peaks of significantly high intensity suggesting improved electrocatalytic activity. Butyrate production is improved by 1.3- and 1.4-folds for SCG and STL, respectively, which could be associated with the enrichment of different fermentative and exoelectrogenic class of bacteria such as Clostridia, Bacteroidia, and Deltaproteobacteria. These results highlight the feasibility of using STL and SCG cathodes for improving MES performance and VFA production.

Data Availability

Data is available on request.

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper.

Acknowledgments

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF2018R1A6A1A03024962) and the Ministry of Science and ICT (NRF-2020R1A2C2100746).

Supplementary Materials

Microbial culture/sludge: information regarding the initial inoculum source and pretreatment. Media and culture conditions: composition of growth media and trace element solution along with microbial enrichment conditions. Microbial community analysis: detailed description of microbial community analysis process. Table S1: primer and template details for microbial community analysis. (Supplementary Materials)

References

S. Bajracharya, K. Vanbroekhoven, C. J. N. Buisman, D. Pant, and D. P. B. T. B. Strik, “Application of gas diffusion biocathode in microbial electrosynthesis from carbon dioxide,” Environmental Science and Pollution Research, vol. 23, no. 22, pp. 22292–22308, 2016.
View at: Publisher Site | Google Scholar
T. Zhang, H. Nie, T. S. Bain et al., “Improved cathode materials for microbial electrosynthesis,” Energy & Environmental Science, vol. 6, no. 1, pp. 217–224, 2013.
View at: Publisher Site | Google Scholar
L. Jourdin, M. Winkelhorst, B. Rawls, C. J. N. Buisman, and D. P. B. T. B. Strik, “Enhanced selectivity to butyrate and caproate above acetate in continuous bioelectrochemical chain elongation from CO₂: steering with CO₂ loading rate and hydraulic retention time,” Bioresource Technology Reports, vol. 7, article 100284, 2019.
View at: Publisher Site | Google Scholar
K. Tahir, W. Miran, J. Jang et al., “A novel MXene-coated biocathode for enhanced microbial electrosynthesis performance,” Chemical Engineering Journal, vol. 381, article 122687, 2020.
View at: Publisher Site | Google Scholar
C. Santoro, C. Arbizzani, B. Erable, and I. Ieropoulos, “Microbial fuel cells: from fundamentals to applications. A review,” Journal of Power Sources, vol. 356, pp. 225–244, 2017.
View at: Publisher Site | Google Scholar
Y. Hindatu, M. S. M. Annuar, and A. M. Gumel, “Mini-review: anode modification for improved performance of microbial fuel cell,” Renewable and Sustainable Energy Reviews, vol. 73, pp. 236–248, 2017.
View at: Publisher Site | Google Scholar
T. Cai, L. Meng, G. Chen et al., “Application of advanced anodes in microbial fuel cells for power generation: a review,” Chemosphere, vol. 248, article 125985, 2020.
View at: Publisher Site | Google Scholar
L. Zhang, W. He, J. Yang et al., “Bread-derived 3D macroporous carbon foams as high performance free-standing anode in microbial fuel cells,” Biosensors & Bioelectronics, vol. 122, pp. 217–223, 2018.
View at: Publisher Site | Google Scholar
A. A. Yaqoob, M. N. M. Ibrahim, and K. Umar, “Biomass-derived composite anode electrode: synthesis, characterizations, and application in microbial fuel cells (MFCs),” Journal of Environmental Chemical Engineering, vol. 9, no. 5, article 106111, 2021.
View at: Publisher Site | Google Scholar
K. Tahir, W. Miran, J. Jang et al., “MXene-coated biochar as potential biocathode for improved microbial electrosynthesis system,” Science of The Total Environment, vol. 773, article 145677, 2021.
View at: Publisher Site | Google Scholar
J. Zhang, J. Li, D. Ye, X. Zhu, Q. Liao, and B. Zhang, “Tubular bamboo charcoal for anode in microbial fuel cells,” Journal of Power Sources, vol. 272, pp. 277–282, 2014.
View at: Publisher Site | Google Scholar
Q. Chen, W. Pu, H. Hou et al., “Activated microporous-mesoporous carbon derived from chestnut shell as a sustainable anode material for high performance microbial fuel cells,” Bioresource Technology, vol. 249, pp. 567–573, 2018.
View at: Publisher Site | Google Scholar
R. Wang, D. Liu, M. Yan et al., “Three-dimensional high performance free-standing anode by one-step carbonization of pinecone in microbial fuel cells,” Bioresource Technology, vol. 292, article 121956, 2019.
View at: Publisher Site | Google Scholar
T. Negi, Y. Kumar, R. Sirohi et al., “Advances in bioconversion of spent tea leaves to value-added products,” Bioresource Technology, vol. 346, article 126409, 2022.
View at: Publisher Site | Google Scholar
E. Sermyagina, C. L. M. Martinez, M. Nikku, and E. Vakkilainen, “Spent coffee grounds and tea leaf residues: characterization, evaluation of thermal reactivity and recovery of high-value compounds,” Biomass and Bioenergy, vol. 150, article 106141, 2021.
View at: Publisher Site | Google Scholar
J. Simões, F. M. Nunes, M. R. Domingues, and M. A. Coimbra, “Extractability and structure of spent coffee ground polysaccharides by roasting pre-treatments,” Carbohydrate Polymers, vol. 97, no. 1, pp. 81–89, 2013.
View at: Publisher Site | Google Scholar
M. K. Afdhol, H. Z. Lubis, and C. P. Siregar, “Production of bioethanol from spent tea and potential used in petroleum region,” Journal of Earth Energy Engineering, vol. 8, no. 1, pp. 21–26, 2019.
View at: Google Scholar
A. W. Go, T. Y. N. Pham, Y. H. Ju, R. C. Agapay, A. E. Angkawijaya, and K. L. Quijote, “Extraction of lipids from post-hydrolysis spent coffee grounds for biodiesel production with hexane as solvent: kinetic and equilibrium data,” Biomass and Bioenergy, vol. 140, article 105704, 2020.
View at: Publisher Site | Google Scholar
H. Zhu, Z. Zhang, Y. Zhou et al., “Porous co, N co-doped carbon derived from tea residue as efficient cathode catalyst in microbial fuel cells for swine wastewater treatment and the microbial community analysis,” Journal of Water Process Engineering, vol. 45, article 102471, 2022.
View at: Publisher Site | Google Scholar
Y. H. Hung, T. Y. Liu, and H. Y. Chen, “Renewable coffee waste-derived porous carbons as anode materials for high-performance sustainable microbial fuel cells,” ACS Sustainable Chemistry & Engineering, vol. 7, no. 20, pp. 16991–16999, 2019.
View at: Publisher Site | Google Scholar
X. Qu, W. Kang, C. Lai, C. Zhang, and S. W. Hong, “A simple route to produce highly efficient porous carbons recycled from tea waste for high-performance symmetric supercapacitor electrodes,” Molecules, vol. 27, no. 3, p. 791, 2022.
View at: Publisher Site | Google Scholar
Z. Dong, H. Wang, S. Tian et al., “Fluidized granular activated carbon electrode for efficient microbial electrosynthesis of acetate from carbon dioxide,” Bioresource Technology, vol. 269, pp. 203–209, 2018.
View at: Publisher Site | Google Scholar
K. Tahir, N. Maile, A. A. Ghani, B. Kim, J. Jang, and D. S. Lee, “Development of a three-dimensional macroporous sponge biocathode coated with carbon nanotube-MXene composite for high-performance microbial electrosynthesis systems,” Bioelectrochemistry, vol. 146, article 108140, 2022.
View at: Publisher Site | Google Scholar
K. Tahir, M. Hussain, N. Maile, A. A. Ghani, B. Kim, and D. S. Lee, “Microbially catalyzed enhanced bioelectrochemical performance using covalent organic framework‐modified anode in a microbial fuel cell,” International Journal of Energy Research, vol. 46, no. 12, pp. 17003–17014, 2022.
View at: Publisher Site | Google Scholar
A. R. Rowe, S. Xu, E. Gardel et al., “Methane-linked mechanisms of electron uptake from cathodes by Methanosarcina barkeri,” mBio, vol. 10, no. 2, pp. 1–12, 2019.
View at: Publisher Site | Google Scholar
C. J. Kirubaharan, K. Santhakumar, G. Gnana Kumar, N. Senthilkumar, and J. H. Jang, “Nitrogen doped graphene sheets as metal free anode catalysts for the high performance microbial fuel cells,” International Journal of Hydrogen Energy, vol. 40, no. 38, pp. 13061–13070, 2015.
View at: Publisher Site | Google Scholar
L. Chen, P.-L. Tremblay, S. Mohanty, K. Xu, and T. Zhang, “Electrosynthesis of acetate from CO₂ by a highly structured biofilm assembled with reduced graphene oxide–tetraethylene pentamine,” Journal of Materials Chemistry A, vol. 4, no. 21, pp. 8395–8401, 2016.
View at: Publisher Site | Google Scholar
K. Tahir, W. Miran, J. Jang, S. H. Woo, and D. S. Lee, “Enhanced product selectivity in the microbial electrosynthesis of butyrate using a nickel ferrite-coated biocathode,” Environmental Research, vol. 196, article 110907, 2021.
View at: Publisher Site | Google Scholar
L. A. Canci, M. de Toledo Benassi, C. Canan, D. L. Kalschne, and E. Colla, “Antimicrobial potential of aqueous coffee extracts against pathogens and Lactobacillus species: A food matrix application,” Food Bioscience, vol. 47, article 101756, 2022.
View at: Publisher Site | Google Scholar
N. Aryal, P.-L. Tremblay, M. Xu, A. E. Daugaard, and T. Zhang, “Highly Conductive Poly(3,4-ethylenedioxythiophene) Polystyrene Sulfonate Polymer Coated Cathode for the Microbial Electrosynthesis of Acetate From Carbon Dioxide,” Frontiers in Energy Research, vol. 6, p. 72, 2018.
View at: Publisher Site | Google Scholar
Y. Feng, Q. Yang, X. Wang, and B. E. Logan, “Treatment of carbon fiber brush anodes for improving power generation in air- cathode microbial fuel cells,” Journal of Power Sources, vol. 195, no. 7, pp. 1841–1844, 2010.
View at: Publisher Site | Google Scholar
D. Liu, R. Wang, W. Chang et al., “Ti₃C₂MXene as an excellent anode material for high-performance microbial fuel cells,” Journal of Materials Chemistry A, vol. 6, no. 42, pp. 20887–20895, 2018.
View at: Publisher Site | Google Scholar
H. Richter, K. P. Nevin, H. Jia, D. A. Lowy, D. R. Lovley, and L. M. Tender, “Cyclic voltammetry of biofilms of wild type and mutant Geobacter sulfurreducens on fuel cell anodes indicates possible roles of OmcB, OmcZ, type IV pili, and protons in extracellular electron transfer,” Energy & Environmental Science, vol. 2, no. 5, pp. 506–516, 2009.
View at: Publisher Site | Google Scholar
X. Jin, F. Guo, Z. Liu, Y. Liu, and H. Liu, “Enhancing the electricity generation and nitrate removal of microbial fuel cells with a novel denitrifying exoelectrogenic strain EB-1,” Frontiers in Microbiology, vol. 9, p. 2633, 2018.
View at: Publisher Site | Google Scholar
P. Batlle-Vilanova, S. Puig, R. Gonzalez-Olmos, M. D. Balaguer, and J. Colprim, “Continuous acetate production through microbial electrosynthesis from CO₂ with microbial mixed culture,” Journal of Chemical Technology and Biotechnology, vol. 91, no. 4, pp. 921–927, 2016.
View at: Publisher Site | Google Scholar
J. A. Modestra and S. V. Mohan, “Microbial electrosynthesis of carboxylic acids through CO₂ reduction with selectively enriched biocatalyst: microbial dynamics,” Journal of CO₂ Utilization, vol. 20, pp. 190–199, 2017.
View at: Publisher Site | Google Scholar
H. Y. Yang, Y. X. Wang, C. S. He et al., “Redox mediator-modified biocathode enables highly efficient microbial electro- synthesis of methane from carbon dioxide,” Applied Energy, vol. 274, article 115292, 2020.
View at: Publisher Site | Google Scholar
A. Carmona, Investigation of Electron Transfer Mechanisms in Electrochemically Active Microbial Biofilms, Institute of Environmental and Sustainable Chemistry, Technische Universität Braunschweig, Germany, 2012.
S. Khilari, S. Pandit, J. L. Varanasi, D. Das, and D. Pradhan, “Bifunctional manganese ferrite/polyaniline hybrid as electrode material for enhanced energy recovery in microbial fuel cell,” ACS Applied Materials & Interfaces, vol. 7, no. 37, pp. 20657–20666, 2015.
View at: Publisher Site | Google Scholar
J. M. Sonawane, S. A. Patil, P. C. Ghosh, and S. B. Adeloju, “Low-cost stainless-steel wool anodes modified with polyaniline and polypyrrole for high-performance microbial fuel cells,” Journal of Power Sources, vol. 379, pp. 103–114, 2018.
View at: Publisher Site | Google Scholar
M. Hu, X. Li, J. Xiong et al., “Nano-Fe3C@PGC as a novel low-cost anode electrocatalyst for superior performance microbial fuel cells,” Biosensors & Bioelectronics, vol. 142, article 111594, 2019.
View at: Publisher Site | Google Scholar
D. F. R. Doud, R. M. Bowers, F. Schulz et al., “Function-driven single-cell genomics uncovers cellulose-degrading bacteria from the rare biosphere,” The ISME Journal, vol. 14, no. 3, pp. 659–675, 2020.
View at: Publisher Site | Google Scholar
V. V. Kadnikov, A. V. Mardanov, A. V. Beletsky, O. V. Karnachuk, and N. V. Ravin, “Microbial life in the deep subsurface aquifer illuminated by metagenomics,” Frontiers in Microbiology, vol. 11, p. 572252, 2020.
View at: Publisher Site | Google Scholar
D. Nosek and A. Cydzik-Kwiatkowska, “Microbial structure and energy generation in microbial fuel cells powered with waste anaerobic digestate,” Energies, vol. 13, no. 18, p. 4712, 2020.
View at: Publisher Site | Google Scholar
Y. Yoshimura, K. Nakashima, M. Kato et al., “Electricity generation from rice bran by a microbial fuel cell and the influence of hydrodynamic cavitation pretreatment,” ACS Omega, vol. 3, no. 11, pp. 15267–15271, 2018.
View at: Publisher Site | Google Scholar
K. Tahir, W. Miran, J. Jang et al., “Carbamazepine biodegradation and volatile fatty acids production by selectively enriched sulfate-reducing bacteria and fermentative acidogenic bacteria,” Journal of Chemical Technology and Biotechnology, vol. 96, no. 3, pp. 592–602, 2021.
View at: Publisher Site | Google Scholar
M. Peces, S. Astals, P. D. Jensen, and W. P. Clarke, “Transition of microbial communities and degradation pathways in anaerobic digestion at decreasing retention time,” New Biotechnology, vol. 60, pp. 52–61, 2021.
View at: Publisher Site | Google Scholar
A. J. M. Stams and T. A. Hansen, “Fermentation of glutamate and other compounds by Acidaminobacter hydrogenoformans gen. Nov. sp. nov., an obligate anaerobe isolated from black mud. Studies with pure cultures and mixed cultures with sulfate-reducing and methanogenic bacteria,” Archives of Microbiology, vol. 137, no. 4, pp. 329–337, 1984.
View at: Publisher Site | Google Scholar
Q. Bei, J. Peng, and W. Liesack, “Shedding light on the functional role of the Ignavibacteria in Italian rice field soil: A meta-genomic/transcriptomic analysis,” Soil Biology and Biochemistry, vol. 163, article 108444, 2021.
View at: Publisher Site | Google Scholar

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Copyright © 2023 Khurram Tahir et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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