Article
Biotechnology & Applied Microbiology
Fernanda Jimenez Otero, Grayson L. Chadwick, Matthew D. Yates, Rebecca L. Mickol, Scott H. Saunders, Sarah M. Glaven, Jeffrey A. Gralnick, Dianne K. Newman, Leonard M. Tender, Victoria J. Orphan, Daniel R. Bond
Summary: A study on a strain of Geobacter sulfurreducens lacking four of five outer membrane cytochrome complexes found that its biofilm growth is faster and produces greater current density. This increased performance is attributed to denser cell packing close to the electrode and higher metabolic rates per cell, as indicated by increased rates of N-15 incorporation. Additionally, the engineered strain shows a higher rate of electron transfer through biofilms compared to the wild type, suggesting a streamlined electron transfer pathway for enhanced current production.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2021)
Article
Microbiology
Jie Jiang, Pengchen He, Ying Luo, Zhaofeng Peng, Yongguang Jiang, Yidan Hu, Lei Qi, Xiuzhu Dong, Yiran Dong, Liang Shi
Summary: The pilA-N, omcE, omcS, omcT, and omcZ genes of Geobacter sulfurreducens have different roles in extracellular electron transfer (EET), enabling efficient EET reactions with substrates of different properties.
FRONTIERS IN MICROBIOLOGY
(2023)
Article
Biotechnology & Applied Microbiology
Jia-Qi Liu, Xin Ma, Dong-Feng Liu, Chuan-Wang Yang, Dao-Bo Li, Di Min, Han-Qing Yu
Summary: Dissimilatory metal-reducing bacteria (DMRB) play important roles in geochemical cycling, biocorrosion, environmental remediation, and bioenergy generation. This study found that the released c-type cytochromes (c-Cyts) from Geobacter sulfurreducens can promote microbial extracellular electron transfer, affect the physiological state of microbial community, and modify electron acceptors.
BIOTECHNOLOGY AND BIOENGINEERING
(2023)
Article
Multidisciplinary Sciences
Xiaomeng Liu, Toshiyuki Ueki, Hongyan Gao, Trevor L. Woodard, Kelly P. Nevin, Tianda Fu, Shuai Fu, Lu Sun, Derek R. Lovley, Jun Yao
Summary: Using microbial biofilms as renewable materials for fabricating clean energy harvesting devices can generate continuous electricity from evaporating water, enhancing sustainability.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Peter J. Dahl, Sophia M. Yi, Yangqi Gu, Atanu Acharya, Catharine Shipps, Jens Neu, J. Patrick O'Brien, Uriel N. Morzan, Subhajyoti Chaudhuri, Matthew J. Guberman-Pfeffer, Dennis Vu, Sibel Ebru Yalcin, Victor S. Batista, Nikhil S. Malvankar
Summary: Geobacter sulfurreducens transports respiratory electrons over micrometers through nanowires composed of polymerized cytochrome OmcS. Individual nanowires exhibit hopping conductance and show a significant increase in their intrinsic conductance upon cooling. The cooling effect is caused by the rearrangement of hydrogen bonding networks in the nanowires, resulting in a temperature-sensitive switch for charge transport controlled by the protein surrounding the hemes.
Article
Biotechnology & Applied Microbiology
Lewis Grozinger, Elizabeth Heidrich, Angel Goni-Moreno
Summary: Synthetic biology utilizes molecular biology to create genetic circuits that can perform computations. These circuits process inputs and produce outputs based on predefined rules encoded in genetic parts. However, recent advancements in the field have shifted towards using mechanisms beyond genetic parts for engineering biological circuits. This study explores the use of electrogenic processes for circuit design and presents a model of a hybrid genetic and electrogenetic toggle switch operating in a biofilm attached to an electrode. Computational simulations were conducted to identify circuit design principles that result in bistability, providing a foundation for the rational design and implementation of hybrid devices that can be controlled genetically and electronically.
MICROBIAL BIOTECHNOLOGY
(2023)
Article
Biochemistry & Molecular Biology
Sergio Martinez-Bahena, Alberto Hernandez-Eligio, Guillermo Antonio Huerta-Miranda, Dulce Castrejon-Lopez, Margarita Miranda-Hernandez, Katy Juarez
Summary: Type IV pili and >100c-type cytochromes in Geobacter sulfurreducens play a crucial role in extracellular electron transfer (EET) towards metal oxides and electrodes. A study reveals that the GSU1771 gene is involved in regulating EET and the formation of electroactive biofilms. The deletion of this gene enhances the reduction of Fe(III) oxides and leads to thicker biofilms with higher electrical current production.
BIOELECTROCHEMISTRY
(2022)
Article
Biochemistry & Molecular Biology
Bernd Giese, Maksym Karamash, Katharina M. Fromm
Summary: This review describes the molecular mechanisms of respiratory processes in biological redox reactions that ensure redox homeostasis in a compartmentalized setup. It highlights the progress made in mechanistic studies on long-distance electron transfer through metal-free peptides and proteins.
Article
Biochemistry & Molecular Biology
Marta A. A. Silva, Ana P. P. Fernandes, David L. L. Turner, Carlos A. A. Salgueiro
Summary: Periplasmic nanowires and electric conductive filaments made of c-type cytochromes from Geobacter sulfurreducens bacterium are crucial for electron storage and/or extracellular electron transfer. The assignment of the heme proton NMR signals for domains C and D in the nanowire cytochrome GSU1996 was obtained and used to guide the assignment of the corresponding signals in the hexaheme bi-domain CD. This new strategy provides a way to functionally characterize large multiheme cytochromes.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Microbiology
Monir Mollaei, Maria Suarez-Diez, Vicente T. Sedano-Nunez, Sjef Boeren, Alfons J. M. Stams, Caroline M. Plugge
Summary: The study suggests that the interspecies electron transfer (IET) mechanism in the SF-GS coculture may involve both direct electron transfer (DIET) and hydrogen/formate transfer (HFIT), indicating a complex interaction between the two species.
FRONTIERS IN MICROBIOLOGY
(2021)
Article
Biology
Fengbin Wang, Chi Ho Chan, Victor Suciu, Khawla Mustafa, Madeline Ammend, Dong Si, Allon Hochbaum, Edward H. Egelman, Daniel R. Bond
Summary: Early genetic and structural observations suggested that metal-reducing organisms like Geobacter had extracellular conductive filaments composed of type IV pili. However, recent research has shown that bacterial c-type cytochromes can also form extracellular filaments for long-range electron transport. Cryo-electron microscopy was used to determine the structure of a third extracellular filament, formed from Geobacter sulfurreducens octaheme cytochrome, OmcZ. The structure of OmcZ differs from that of OmcS and OmcE, indicating that conductive cytochrome polymers likely arose independently from different ancestral multiheme proteins.
Article
Biochemistry & Molecular Biology
Marisa R. Ferreira, Tomas M. Fernandes, David L. Turner, Carlos A. Salgueiro
Summary: Electroactive Geobacter bacteria have the ability to perform extracellular electron transfer and produce electric current while interacting with electrodes. This study investigates the structural and functional properties of the periplasmic triheme PpcA-family cytochromes in Geobacter metallireducens, providing important insights into their role in electron transfer efficiency and functionality.
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
(2022)
Article
Agricultural Engineering
Haiquan Dong, Jun Cheng, Hui Li, Liangchen Yue, Rongxin Xia, Junhu Zhou
Summary: This study investigated the use of co-culturing Geobacter sulfurreducens with mixed methanogens to address the issue of poor utilization of H-2 and CO2 in biomethane conversion. The results showed that, with a specific inoculation volume ratio, there was a significant improvement in methane production and H2 conversion efficiency. Furthermore, electrochemical detection and fluorescence spectra analysis revealed an enhanced metabolic capacity and the ability for direct interspecific electron transfer to produce CH4 in the co-culture system. Additionally, gene sequencing demonstrated the establishment of a mutualistic relationship between G. sulfurreducens and Methanoculleus.
BIORESOURCE TECHNOLOGY
(2022)
Article
Environmental Sciences
Zheng Zhuang, Guiqin Yang, Li Zhuang
Summary: The study investigated the role of exopolysaccharides in electroactive biofilms by constructing an exopolysaccharides-deficient Geobacter sulfurreducens-based BES. The findings demonstrated the essential role of exopolysaccharides in extracellular electron transfer (EET) and early biofilm formation, with pili playing a compensatory role in biofilm formation. The mutant biofilm had lower cell viability, thinner biofilm, and decreased electrochemical activity compared to the wild-type biofilm.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Review
Microbiology
Thomas Andrew Clarke
Summary: This article describes the EET pathways of the electrogenic bacteria Shewanella oneidensis and Geobacter sulferreducens, and compares the differences in their electron transfer mechanisms, which significantly impact substrate choice and bacterial lifestyle.
CURRENT OPINION IN MICROBIOLOGY
(2022)
Review
Electrochemistry
Rui Gao, Suanny Mosquera-Romero, Eleftheria Ntagia, Xiaofei Wang, Korneel Rabaey, Luiza Bonin
Summary: Electrochemical technologies offer the possibility of simultaneous removal of persistent pollutants and resource recovery from wastewater, with the advantages of low chemical input, cost-effectiveness, and reduced water consumption. Key challenges include material cost and longevity, process efficiency and selectivity, and the complexity of wastewater matrices.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Review
Biotechnology & Applied Microbiology
Pieter Ostermeyer, Luiza Bonin, Luis Fernando Leon-Fernandez, Xochitl Dominguez-Benetton, Tom Hennebel, Korneel Rabaey
Summary: The text discusses the development of biological treatment for metallurgical wastewaters, highlighting the drawbacks of passive and active treatment systems and the advantages of electrified biological systems. It also addresses the challenges faced by bioelectrochemical systems in high rate applications and emphasizes the importance of future research focusing on the development and effectiveness of electrified bioreactors.
MICROBIAL BIOTECHNOLOGY
(2022)
Article
Biotechnology & Applied Microbiology
Pamela Ceron-Chafla, Cristina Garcia-Timermans, Jo de Vrieze, Ramon Ganigue, Nico Boon, Korneel Rabaey, Jules B. van Lier, Ralph E. F. Lindeboom
Summary: Fermentation at elevated hydrostatic pressure can alter product selectivity, and the relationship between incubation temperature and halotolerance plays a key role in microbial responses to high pressure. Moderate temperatures do not limit biomass yield and fermentation, while low and high temperatures impose constraints on growth and product formation.
BIOTECHNOLOGY AND BIOENGINEERING
(2022)
Article
Engineering, Environmental
Manel Garrido-Baserba, Irene Barnosell, Maria Molinos-Senante, David L. Sedlak, Korneel Rabaey, Oliver Schraa, Marta Verdaguer, Diego Rosso, Manel Poch
Summary: Water systems need to become more locally robust and sustainable. Decentralized treatment has the potential to improve the technical, environmental, and economic performance. Assessments on various building types demonstrate that decentralized systems can satisfy water demand and reduce construction costs under certain climatic conditions.
Article
Microbiology
Alberto Scoma, Way Cern Khor, Marta Coma, Robert Heyer, Ruben Props, Tim Bouts, Dirk Benndorf, Desheng Li, Hemin Zhang, Korneel Rabaey
Summary: The gut microbiome of giant pandas plays a significant role in their nutrition by helping with digestion processes, and experimental results show that green leaves are mainly fermented into ethanol while yellow pith is mainly fermented into lactate. Further research is needed to understand the effects of pH, dung samples, fermentation products, and bamboo supply on pandas.
Editorial Material
Biotechnology & Applied Microbiology
Silvio Matassa, Pascal Boeckx, Jos Boere, Jan Willem Erisman, Miao Guo, Raffaele Manzo, Francis Meerburg, Stefano Papirio, Ilje Pikaar, Korneel Rabaey, Diederik Rousseau, Jerald Schnoor, Peter Smith, Erik Smolders, Stefan Wuertz, Willy Verstraete
Summary: Nitrogen is crucial for the production of nutritious feeds and foods, but the production and use of fertilizer nitrogen pose a major threat to environmental health and sustainability. It is important to promote consumer acceptance and awareness of proteins produced by highly effective microorganisms as an alternative to proteins obtained from plants and animals with low nitrogen efficiencies. Additionally, recovering and upgrading used nitrogen from secondary resources and integrating biological nitrogen fixation into feed and food supply chains are promising solutions for a more sustainable agriculture.
MICROBIAL BIOTECHNOLOGY
(2023)
Correction
Biotechnology & Applied Microbiology
L. Van Peteghem, M. Sakarika, S. Matassa, K. Rabaey
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Engineering, Environmental
Eleni Stylianou, Jose M. Carvajal-Arroyo, Dimitrios Ladakis, Carol Sze Ki Lin, Vera Essmann, Sebastin Dorr, Jakob Marbach, Korneel Rabaey, Apostolis Koutinas, Chrysanthi Pateraki
Summary: A novel electrochemical membrane bioreactor (EMB) integrating succinic acid (SA) production and in situ separation was used with hydrolysates from the organic fraction of municipal solid waste (OFMSW) as feedstock. The fermentation process was optimized to achieve high SA productivity and efficiency, and the SA crystals were successfully purified for further applications. Scale-up of the process was influenced by yeast cell viability, cell design, and EMB configuration. Overall, this study demonstrated the potential of the EMB system for sustainable SA production and purification.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Kai Cui, Kun Guo, Jose M. Carvajal-Arroyo, Jan Arends, Korneel Rabaey
Summary: Currently, most microbial electrosynthesis (MES) reactors are driven by biofilms, whether the cathode electron transfer is direct or indirect. The formation of cathode biofilms is time-consuming, and the current density achieved on these biofilms is relatively low. However, non-biofilm-driven MES faces the challenge of maintaining good Columbic efficiency (CE) at high current densities. In this study, a novel electro-H2 bubble column reactor with an external hollow fiber membrane gas-liquid contactor was developed to address this challenge. The reactor demonstrated efficient conversion of electrolytically-produced H2 and externally-supplied CO2 into acetate, with high acetate production rates and CE.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Seppe Ongena, Arjen Van de Walle, Suanny Mosquera-Romero, Nele Driesen, Leonardo Gutierrez, Korneel Rabaey
Summary: Greywater is a viable source for water reuse at the household or building level, and two treatment approaches, MBR and MBBR, were compared in this study. The results showed that both MBR and MBBR met most water quality requirements for greywater reuse, but MBR had a smaller reactor volume and delayed membrane fouling compared to MBBR. However, neither system allowed adequate nitrogen removal, and MBBR had issues with effluent chemical oxygen demand and turbidity requirements. UV disinfection was more efficient than electrochemical disinfection in the long run. Proposed improvements aim to optimize the performance of both treatment trains and disinfection processes for small-scale greywater treatment for reuse.
Article
Ecology
Pieter Candry, Grayson L. Chadwick, Jose Maria Caravajal-Arroyo, Tim Lacoere, Mari-Karoliina Henriikka Winkler, Ramon Ganigue, Victoria J. Orphan, Korneel Rabaey
Summary: This study investigates the spatial organization and growth activity patterns of granular biofilms producing medium-chain carboxylic acids (MCCA) and reveals that key functional guilds are not stratified. The outer layers of the biofilms consist of Olsenella and Oscillospiraceae, while deeper layers contain less active bacteria. The study also suggests that Oscillospiraceae switch from sugars to lactic acid as a substrate and physical processes may contribute to the lenticular biofilm morphology.
Review
Green & Sustainable Science & Technology
Arjen Van de Walle, Minseok Kim, Md Kawser Alam, Xiaofei Wang, Di Wu, Smruti Ranjan Dash, Korneel Rabaey, Jeonghwan Kim
Summary: Sustainable water management is crucial for ensuring access to safe water and addressing challenges such as climate change, urbanization, and population growth. Greywater, which accounts for 50-80% of daily wastewater generation in households and has low organic strength and high volume, requires separate treatment strategies due to its characteristics. Greywater reuse can enhance the resilience and adaptability of local water systems, reduce transport costs, and achieve fit-for-purpose reuse. Various biological and physicochemical treatment technologies can produce treated water suitable for reuse. Overcoming challenges such as greywater quality variance, legal framework, monitoring and control systems, and consumer perspective is important. The potential water and energy savings and sustainable future of greywater reuse in an urban context are also discussed.
ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY
(2023)
Article
Green & Sustainable Science & Technology
Xiaoting Zhang, Tyler Arbour, Daijun Zhang, Shiqiang Wei, Korneel Rabaey
Summary: Microbial electrosynthesis (MES) can produce multicarbon compounds from CO₂ using electricity as the energy source. This study assessed MES under 35-60 g/L salinity and found that acetate production decreased over time under high salinity conditions. Carbonate precipitation on cathodes inhibited CO₂ supply, electrode contact, and H₂ production, leading to reduced acetate production. By adjusting the levels of Ca²⁺ and Mg²⁺ in the reactors, stable acetate production was achieved. The research also highlighted the dominance of Acetobacterium and Sphaerochaeta bacteria in the MES system.
ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY
(2023)
Article
Green & Sustainable Science & Technology
Arjen Van de Walle, Elena Torfs, Dorien Gaublomme, Korneel Rabaey
Summary: This study explores the potential of extreme decentralization in water resource management, proposing key performance indicators through modeling and quantitative assessment, and addressing the issue of contaminant accumulation in circular systems. The findings provide support for the operation and technological decision-making of decentralized household-scale water systems, as well as guidance for future water policy-making.
ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY
(2022)
Article
Green & Sustainable Science & Technology
Pieter Ostermeyer, Josefien Van Landuyt, Luiza Bonin, Karel Folens, Adam Williamson, Tom Hennebel, Korneel Rabaey
Summary: This study successfully treated metallurgical wastewater with high sulfate concentrations using two hydrogenotrophic granular activated carbon expanded bed bioreactors operating at pH 8 ± 0.15. The reactors achieved a high sulfate removal rate of 7.08 g L-1 and a sulfate reduction rate of 27.2 g L-1 d(-1) while effectively removing various metals, nitrates, and sulfates below discharge limits.
ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY
(2022)
