Microbial electrosynthesis system (MES) is a promising method that can use carbon dioxide,which is a greenhouse gas,to produce methane which acts as an energy source,without using organic substances.However,this bioel...Microbial electrosynthesis system (MES) is a promising method that can use carbon dioxide,which is a greenhouse gas,to produce methane which acts as an energy source,without using organic substances.However,this bioelectrical reduction reaction can proceed at a certain high applied voltage when coupled with water oxidation in the anode coated with metallic catalyst.When coupled with the oxidation of HS–to SO_(4)^(2-),methane production is thermodynamically more feasible,thus implying its production at a considerably lower applied voltage.In this study,we demonstrated the possibility of electrotrophic methane production coupled with HS–oxidation in a cost-effective bioanode chamber in the MES without organic substrates at a low applied voltage of 0.2 V.In addition,microbial community analyses of biomass enriched in the bioanode and biocathode were used to reveal the most probable pathway for methane production from HS–oxidation.In the bioanode,electroautotrophic SO_(4)^(2-)production accompanied with electron donation to the electrode is performed mainly by the following two steps:first,incomplete sulfide oxidation to sulfur cycle intermediates (SCI) is performed;then the produced SCI are disproportionated to HS^(–)and SO_(4)^(2-).In the biocathode,methane is produced mainly via H_(2)and acetate by electronaccepting syntrophic bacteria,homoacetogens,and acetoclastic archaea.Here,a new ecofriendly MES with biological H_(2)S removal is established.展开更多
Methane is produced in a microbial electrosynthesis system(MES) without organic substrates. However, a relatively high applied voltage is required for the bioelectrical reactions.In this study, we demonstrated that el...Methane is produced in a microbial electrosynthesis system(MES) without organic substrates. However, a relatively high applied voltage is required for the bioelectrical reactions.In this study, we demonstrated that electrotrophic methane production at the biocathode was achieved even at a very low voltage of 0.1 V in an MES, in which abiotic HS-oxidized to SO_(4)^(2-) at the anodic carbon-cloth surface coated with platinum powder. In addition, microbial community analysis revealed the most probable pathway for methane production from electrons. First, electrotrophic H_(2) was produced by syntrophic bacteria, such as Syntrophorhabdus, Syntrophobacter, Syntrophus, Leptolinea, and Aminicenantales, with the direct acceptance of electrons at the biocathode. Subsequently, most of the produced H_(2) was converted to acetate by homoacetogens, such as Clostridium and Spirochaeta 2. In conclusion,the majority of the methane was indirectly produced by a large population of acetoclastic methanogens, namely Methanosaeta, via acetate. Further, hydrogenotrophic methanogens,including Methanobacterium and Methanolinea, produced methane via H_(2).展开更多
Microbial electrosynthesis(MES)converts CO_(2)into value-added products such as volatile fatty acids(VFAs)with minimal energy use,but low production titer has limited scale-up and commercialization.Mediated electron t...Microbial electrosynthesis(MES)converts CO_(2)into value-added products such as volatile fatty acids(VFAs)with minimal energy use,but low production titer has limited scale-up and commercialization.Mediated electron transfer via H_(2)on the MES cathode has shown a higher conversion rate than the direct biofilm-based approach,as it is tunable via cathode potential control and accelerates electrosynthesis from CO_(2).Here we report high acetate titers can be achieved via improved in situ H_(2)supply by nickel foam decorated carbon felt cathode in mixed community MES systems.Acetate concentration of 12.5 g L^(-1)was observed in 14 days with nickel-carbon cathode at a poised potential of-0.89 V(vs.standard hydrogen electrode,SHE),which was much higher than cathodes using stainless steel(5.2 g L^(-1))or carbon felt alone(1.7 g L^(-1))with the same projected surface area.A higher acetate concentration of 16.0 g L^(-1)in the cathode was achieved over long-term operation for 32 days,but crossover was observed in batch operation,as additional acetate(5.8 g L^(-1))was also found in the abiotic anode chamber.We observed the low Faradaic efficiencies in acetate production,attributed to partial H_(2)utilization for electrosynthesis.The selective acetate production with high titer demonstrated in this study shows the H_(2)-mediated electron transfer with common cathode materials carries good promise in MES development.展开更多
The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide(CO_(2))emissions,posing an ongoing threat to the ecological security of the Earth.Microbial electrosyn...The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide(CO_(2))emissions,posing an ongoing threat to the ecological security of the Earth.Microbial electrosynthesis(MES)is an innovative energy regeneration strategy that offers a gentle and efficient approach to converting CO_(2) into high-value products.The cathode chamber is a vital component of an MES system and its internal factors play crucial roles in improving the performance of the MES system.Therefore,this review aimed to provide a detailed analysis of the key factors related to the cathode chamber in the MES system.The topics covered include inward extracellular electron transfer pathways,cathode materials,applied cathode potentials,catholyte pH,and reactor configuration.In addition,this review analyzes and discusses the challenges and promising avenues for improving the conversion of CO_(2) into high-value products via MES.展开更多
Wastewater treatment significantly contributes to greenhouse gas emissions,which are further exacerbated by the environmental impact of external chemical additions.In response,microbial electrochemical wastewater refi...Wastewater treatment significantly contributes to greenhouse gas emissions,which are further exacerbated by the environmental impact of external chemical additions.In response,microbial electrochemical wastewater refining has gained prominence at the interdisciplinary frontier of wastewater resource recovery and green bio-manufacturing.Significant progress has been made in utilizing active electrodes to stimulate CO_(2) fixation rates,applying“binary electron donors”to produce high-value-added chemicals,and developing novel processes and equipment.This review explores various aspects of microbial electrochemical wastewater refining,including microbial electrochemical monitoring of water quality,chemical synthesis from diverse carbon sources,and the deployment of pilot-scale systems for generating electricity,hydrogen,and methane,as well as for in-situ remediation.Additionally,it discusses the challenges and future directions,highlighting the importance of understanding mechanisms,advancing electrocatalyst and microbial engineering,and innovating hybrid processes.In conclusion,the widespread adoption of microbial electrochemical wastewater refining is emphasized for resource recovery and sustainable chemical production,ultimately reducing environmental impact.展开更多
Microbial electrosynthesis is a promising alternative to directly convert CO_(2)into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic systems.However,problems arose that the conventional e...Microbial electrosynthesis is a promising alternative to directly convert CO_(2)into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic systems.However,problems arose that the conventional electrocatalysts for hydrogen evolution may produce extensive by-products of reactive oxygen species and cause severe metal leaching,both of which induce strong toxicity toward microorganisms.Moreover,poor stability of electrocatalysts cannot be qualified for long-term operation.These problems may result in poor biocompatibility between electrocatalysts and microorganisms.To solve the bottleneck problem,Co anchored on porphyrinic triazine-based frameworks was synthesized as the electrocatalyst for hydrogen evolution and further coupled with Cupriavidus necator H16.It showed high selectivity for a four-electron pathway of oxygen reduction reaction and low production of reactive oxygen species,owing to the synergistic effect of Co–Nx modulating the charge distribution and adsorption energy of intermediates.Additionally,low metal leaching and excellent stability were observed,which may be attributed to low content of Co and the stabilizing effect of metalloporphyrins.Hence,the electrocatalyst exhibited excellent biocompatibility.Finally,the microbial electrosynthesis system equipped with the electrocatalyst successfully converted CO_(2)to poly-β-hydroxybutyrate.This work drew up a novel strategy for enhancing the biocompatibility of electrocatalysts in microbial electrosynthesis system.展开更多
Abiotic-biological hybrid systems that combine the advantages of abiotic catalysis and biotransformation for the conversion of carbon dioxide(CO2)to value-added chemicals and fuels have emerged as an appealing way to ...Abiotic-biological hybrid systems that combine the advantages of abiotic catalysis and biotransformation for the conversion of carbon dioxide(CO2)to value-added chemicals and fuels have emerged as an appealing way to address the global energy and environmental crisis caused by increased CO2 emission.We illustrate the recent progress in this field.Here,we first review the natural CO2 fixation pathways for an in-depth understanding of the biological CO2 transformation strategy and why a sustainable feed of reducing power is important.Second,we review the recent progress in the construction of abiotic-biological hybrid systems for CO2 transformation from two aspects:(i)microbial electrosynthesis systems that utilize electricity to support whole-cell biological CO2 conversion to products of interest and(ii)photosynthetic semiconductor biohybrid systems that integrate semiconductor nanomaterials with CO2-fixing microorganisms to harness solar energy for biological CO2 transformation.Lastly,we discuss potential approaches for further improvement of abiotic-biological hybrid systems.展开更多
Microbial electrosynthesis(MES)represents a promising approach for converting CO_(2)into organic chemicals.However,its industrial application is hindered by low-value products,such as acetate and methane,and insuffici...Microbial electrosynthesis(MES)represents a promising approach for converting CO_(2)into organic chemicals.However,its industrial application is hindered by low-value products,such as acetate and methane,and insufficient productivity.To address these limitations,coupling acetate production via MES with microbial upgrading to higher-value compounds offers a viable solution.Here we show an inte-grated reactor that recirculates a cell-free medium between an MES reactor hosting anaerobic homo-acetogens(Acetobacterium)and a continuously stirred tank bioreactor hosting aerobic acetate-utilizing bacteria(Alcaligenes)for efficient single-cell protein(SCP)production from CO_(2)and electricity.The reactor achieved a maximum cell dry weight(CDW)of 17.4 g L^(-1),with an average production rate of 1.5 g L^(-1) d^(-1).The protein content of the biomass reached 74%of the dry weight.Moreover,the integrated design significantly reduced wastewater generation,mitigated product inhibition,and enhanced SCP production.These results demonstrate the potential of this integrated reactor for the efficient and sus-tainable production of high-value bioproducts from CO_(2) and electricity using acetate as a key intermediate.展开更多
Electroactive bacteria could perform bi-directional extracellular electron transfer(EET)to exchange electrons and energy with extracellular environments,thus playing a central role in microbial electro-fermentation(EF...Electroactive bacteria could perform bi-directional extracellular electron transfer(EET)to exchange electrons and energy with extracellular environments,thus playing a central role in microbial electro-fermentation(EF)process.Unbalanced fermentation and microbial electrosynthesis are the main pathways to produce value-added chemicals and biofuels.However,the low efficiency of the bi-directional EET is a dominating bottleneck in these processes.In this review,we firstly demonstrate the main bi-directional EET mechanisms during EF,including the direct EET and the shuttle-mediated EET.Then,we review representative milestones and progresses in unbalanced fermentation via anode outward EET and microbial electrosynthesis via inward EET based on these two EET mechanisms in detail.Furthermore,we summarize the main synthetic biology strategies in improving the bi-directional EET and target products synthesis,thus to enhance the efficiencies in unbalanced fermentation and microbial electrosynthesis.Lastly,a perspective on the applications of microbial electro-fermentation is provided.展开更多
基金supported by the Japan Society for the Promotion of Science (JSPS) through a Grant-in-Aid for Scientific Research (No. 17H01300)。
文摘Microbial electrosynthesis system (MES) is a promising method that can use carbon dioxide,which is a greenhouse gas,to produce methane which acts as an energy source,without using organic substances.However,this bioelectrical reduction reaction can proceed at a certain high applied voltage when coupled with water oxidation in the anode coated with metallic catalyst.When coupled with the oxidation of HS–to SO_(4)^(2-),methane production is thermodynamically more feasible,thus implying its production at a considerably lower applied voltage.In this study,we demonstrated the possibility of electrotrophic methane production coupled with HS–oxidation in a cost-effective bioanode chamber in the MES without organic substrates at a low applied voltage of 0.2 V.In addition,microbial community analyses of biomass enriched in the bioanode and biocathode were used to reveal the most probable pathway for methane production from HS–oxidation.In the bioanode,electroautotrophic SO_(4)^(2-)production accompanied with electron donation to the electrode is performed mainly by the following two steps:first,incomplete sulfide oxidation to sulfur cycle intermediates (SCI) is performed;then the produced SCI are disproportionated to HS^(–)and SO_(4)^(2-).In the biocathode,methane is produced mainly via H_(2)and acetate by electronaccepting syntrophic bacteria,homoacetogens,and acetoclastic archaea.Here,a new ecofriendly MES with biological H_(2)S removal is established.
基金supported by the Japan Society for the Promotion of Science(JSPS)as a Grant-in-Aid for Scientific Research(No.17H01300)。
文摘Methane is produced in a microbial electrosynthesis system(MES) without organic substrates. However, a relatively high applied voltage is required for the bioelectrical reactions.In this study, we demonstrated that electrotrophic methane production at the biocathode was achieved even at a very low voltage of 0.1 V in an MES, in which abiotic HS-oxidized to SO_(4)^(2-) at the anodic carbon-cloth surface coated with platinum powder. In addition, microbial community analysis revealed the most probable pathway for methane production from electrons. First, electrotrophic H_(2) was produced by syntrophic bacteria, such as Syntrophorhabdus, Syntrophobacter, Syntrophus, Leptolinea, and Aminicenantales, with the direct acceptance of electrons at the biocathode. Subsequently, most of the produced H_(2) was converted to acetate by homoacetogens, such as Clostridium and Spirochaeta 2. In conclusion,the majority of the methane was indirectly produced by a large population of acetoclastic methanogens, namely Methanosaeta, via acetate. Further, hydrogenotrophic methanogens,including Methanobacterium and Methanolinea, produced methane via H_(2).
基金supported by the Department of Energy Bioenergy Technologies Office under the award DE-EE0008932supported through the Princeton Center for Complex Materials(PCCM),a National Science Foundation(NSF)-MRSEC program(DMR-2011750).
文摘Microbial electrosynthesis(MES)converts CO_(2)into value-added products such as volatile fatty acids(VFAs)with minimal energy use,but low production titer has limited scale-up and commercialization.Mediated electron transfer via H_(2)on the MES cathode has shown a higher conversion rate than the direct biofilm-based approach,as it is tunable via cathode potential control and accelerates electrosynthesis from CO_(2).Here we report high acetate titers can be achieved via improved in situ H_(2)supply by nickel foam decorated carbon felt cathode in mixed community MES systems.Acetate concentration of 12.5 g L^(-1)was observed in 14 days with nickel-carbon cathode at a poised potential of-0.89 V(vs.standard hydrogen electrode,SHE),which was much higher than cathodes using stainless steel(5.2 g L^(-1))or carbon felt alone(1.7 g L^(-1))with the same projected surface area.A higher acetate concentration of 16.0 g L^(-1)in the cathode was achieved over long-term operation for 32 days,but crossover was observed in batch operation,as additional acetate(5.8 g L^(-1))was also found in the abiotic anode chamber.We observed the low Faradaic efficiencies in acetate production,attributed to partial H_(2)utilization for electrosynthesis.The selective acetate production with high titer demonstrated in this study shows the H_(2)-mediated electron transfer with common cathode materials carries good promise in MES development.
基金supported by grants from National Natural Science Foundation of China (32070097 and 91951202)National Key Research and Development Program of China (2019YFA0904800).
文摘The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide(CO_(2))emissions,posing an ongoing threat to the ecological security of the Earth.Microbial electrosynthesis(MES)is an innovative energy regeneration strategy that offers a gentle and efficient approach to converting CO_(2) into high-value products.The cathode chamber is a vital component of an MES system and its internal factors play crucial roles in improving the performance of the MES system.Therefore,this review aimed to provide a detailed analysis of the key factors related to the cathode chamber in the MES system.The topics covered include inward extracellular electron transfer pathways,cathode materials,applied cathode potentials,catholyte pH,and reactor configuration.In addition,this review analyzes and discusses the challenges and promising avenues for improving the conversion of CO_(2) into high-value products via MES.
基金supported by the National Natural Science Foundation of China(52125001,52370033,and 31970106).
文摘Wastewater treatment significantly contributes to greenhouse gas emissions,which are further exacerbated by the environmental impact of external chemical additions.In response,microbial electrochemical wastewater refining has gained prominence at the interdisciplinary frontier of wastewater resource recovery and green bio-manufacturing.Significant progress has been made in utilizing active electrodes to stimulate CO_(2) fixation rates,applying“binary electron donors”to produce high-value-added chemicals,and developing novel processes and equipment.This review explores various aspects of microbial electrochemical wastewater refining,including microbial electrochemical monitoring of water quality,chemical synthesis from diverse carbon sources,and the deployment of pilot-scale systems for generating electricity,hydrogen,and methane,as well as for in-situ remediation.Additionally,it discusses the challenges and future directions,highlighting the importance of understanding mechanisms,advancing electrocatalyst and microbial engineering,and innovating hybrid processes.In conclusion,the widespread adoption of microbial electrochemical wastewater refining is emphasized for resource recovery and sustainable chemical production,ultimately reducing environmental impact.
基金This project was supported by the National Natural Science Foundation of China(Grant Nos.22122812,22075245 and 21961160742)。
文摘Microbial electrosynthesis is a promising alternative to directly convert CO_(2)into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic systems.However,problems arose that the conventional electrocatalysts for hydrogen evolution may produce extensive by-products of reactive oxygen species and cause severe metal leaching,both of which induce strong toxicity toward microorganisms.Moreover,poor stability of electrocatalysts cannot be qualified for long-term operation.These problems may result in poor biocompatibility between electrocatalysts and microorganisms.To solve the bottleneck problem,Co anchored on porphyrinic triazine-based frameworks was synthesized as the electrocatalyst for hydrogen evolution and further coupled with Cupriavidus necator H16.It showed high selectivity for a four-electron pathway of oxygen reduction reaction and low production of reactive oxygen species,owing to the synergistic effect of Co–Nx modulating the charge distribution and adsorption energy of intermediates.Additionally,low metal leaching and excellent stability were observed,which may be attributed to low content of Co and the stabilizing effect of metalloporphyrins.Hence,the electrocatalyst exhibited excellent biocompatibility.Finally,the microbial electrosynthesis system equipped with the electrocatalyst successfully converted CO_(2)to poly-β-hydroxybutyrate.This work drew up a novel strategy for enhancing the biocompatibility of electrocatalysts in microbial electrosynthesis system.
文摘Abiotic-biological hybrid systems that combine the advantages of abiotic catalysis and biotransformation for the conversion of carbon dioxide(CO2)to value-added chemicals and fuels have emerged as an appealing way to address the global energy and environmental crisis caused by increased CO2 emission.We illustrate the recent progress in this field.Here,we first review the natural CO2 fixation pathways for an in-depth understanding of the biological CO2 transformation strategy and why a sustainable feed of reducing power is important.Second,we review the recent progress in the construction of abiotic-biological hybrid systems for CO2 transformation from two aspects:(i)microbial electrosynthesis systems that utilize electricity to support whole-cell biological CO2 conversion to products of interest and(ii)photosynthetic semiconductor biohybrid systems that integrate semiconductor nanomaterials with CO2-fixing microorganisms to harness solar energy for biological CO2 transformation.Lastly,we discuss potential approaches for further improvement of abiotic-biological hybrid systems.
基金sponsored by the"Pioneer"and"Leading Goose"R&D Program of Zhejiang(No.2024C03111)the National Natural Science Foundation of China(No.22208260,No.32300101,No.32270085)the open fund from the Xi'an Key Laboratory of Cl Compound Bioconversion Technology and Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(TSBICIP-CXRC-041 and TSBICIP-IJCP-004).
文摘Microbial electrosynthesis(MES)represents a promising approach for converting CO_(2)into organic chemicals.However,its industrial application is hindered by low-value products,such as acetate and methane,and insufficient productivity.To address these limitations,coupling acetate production via MES with microbial upgrading to higher-value compounds offers a viable solution.Here we show an inte-grated reactor that recirculates a cell-free medium between an MES reactor hosting anaerobic homo-acetogens(Acetobacterium)and a continuously stirred tank bioreactor hosting aerobic acetate-utilizing bacteria(Alcaligenes)for efficient single-cell protein(SCP)production from CO_(2)and electricity.The reactor achieved a maximum cell dry weight(CDW)of 17.4 g L^(-1),with an average production rate of 1.5 g L^(-1) d^(-1).The protein content of the biomass reached 74%of the dry weight.Moreover,the integrated design significantly reduced wastewater generation,mitigated product inhibition,and enhanced SCP production.These results demonstrate the potential of this integrated reactor for the efficient and sus-tainable production of high-value bioproducts from CO_(2) and electricity using acetate as a key intermediate.
基金This research was supported by the National Key Research and Development Program of China(No.2018YFA0901300)Independent Innovation Fund of Tianjin University(0903065070,0903065083,0903065084).
文摘Electroactive bacteria could perform bi-directional extracellular electron transfer(EET)to exchange electrons and energy with extracellular environments,thus playing a central role in microbial electro-fermentation(EF)process.Unbalanced fermentation and microbial electrosynthesis are the main pathways to produce value-added chemicals and biofuels.However,the low efficiency of the bi-directional EET is a dominating bottleneck in these processes.In this review,we firstly demonstrate the main bi-directional EET mechanisms during EF,including the direct EET and the shuttle-mediated EET.Then,we review representative milestones and progresses in unbalanced fermentation via anode outward EET and microbial electrosynthesis via inward EET based on these two EET mechanisms in detail.Furthermore,we summarize the main synthetic biology strategies in improving the bi-directional EET and target products synthesis,thus to enhance the efficiencies in unbalanced fermentation and microbial electrosynthesis.Lastly,a perspective on the applications of microbial electro-fermentation is provided.
