Facing the increasingly severe energy shortage and environmental pollution, electrocatalytic processes using electroactive microorganisms provide a new alternative for achieving environmental-friendly production. Because of its unique respiratory mode and electron transfer ability, Shewanella oneidensis MR-1 has been widely used in the fields of microbial fuel cell, bioelectrosynthesis of value-added chemicals, metal waste treatment and environmental remediation system. The electrochemically active biofilm of S. oneidensis MR-1 is an excellent carrier for transferring the electrons of the electroactive microorganisms. The formation of electrochemically active biofilm is a dynamic and complex process, which is affected by many factors, such as electrode materials, culture conditions, strains and their metabolism. The electrochemically active biofilm plays a very important role in enhancing bacterial environmental stress resistance, improving nutrient uptake and electron transfer efficiency. This paper reviewed the formation process, influencing factors and applications of S. oneidensis MR-1 biofilm in bio-energy, bioremediation and biosensing, with the aim to facilitate and expand its further application.
Bioelectric Energy Sources/microbiology* ; Biofilms ; Electrodes ; Electron Transport ; Shewanella/metabolism*

A microbial fuel cell (MFC)-based microbial electrochemical sensor was developed for real-time on-line monitoring of heavy metals in water environment. The microbial electrochemical sensor was constructed with staggered flow distribution method to optimize the parameters such as external resistance value and external circulation rate. The inhibition of concentration of simulated heavy metal wastewater on voltage under optimal parameters was analyzed. The results showed that the best performance of MFC electrochemical sensor was achieved when the external resistance value was 130 Ω and the external circulation rate was 1.0 mL/min. In this case, the microbial electrochemical sensors were responsive to 1-10 mg/L Cu²⁺, 0.25-1.25 mg/L Cd²⁺, 0.25-1.25 mg/L Cr⁶⁺ and 0.25-1.00 mg/L Hg²⁺ within 60 minutes. The maximum rejection rates of the output voltage were 92.95%, 73.11%, 82.76% and 75.80%, respectively, and the linear correlation coefficients were all greater than 0.95. In addition, the microbial electrochemical sensor showed a good biological reproducibility. The good performance for detecting heavy metals by the newly developed microbial electrochemical sensor may facilitate the real-time on-line monitoring of heavy metals in water environment.
Bioelectric Energy Sources ; Electrodes ; Metals, Heavy/analysis* ; Reproducibility of Results ; Waste Water ; Water

Microbial fuel cell (MFC) is a bioelectrochemical device, that enables simultaneous wastewater treatment and energy generation. However, a few issues such as low output power, high ohmic internal resistance, and long start-up time greatly limit MFCs' applications. MFC anode is the carrier of microbial attachment, and plays a key role in the generation and transmission of electrons. High-quality bioelectrodes have developed into an effective way to improve MFC performance. Conjugated polymers have advantages of low cost, high conductivity, chemical stability and good biocompatibility. The use of conjugated polymers to modify bioelectrodes can achieve a large specific surface area and shorten the charge transfer path, thereby achieving efficient biological electrochemical performance. In addition, bacteria can be coated with nano-scale conjugated polymer and effectively transfer the electrons generated by cells to electrodes. This article reviews the recently reported applications of conjugated polymers in microbial fuel cells, focusing on the MFC anode materials modified by conjugated polymers. This review also systematically analyzes the advantages and limitations of conjugated polymers, and how these composite hybrid bioelectrodes solve practical issues such as low energy output, high inner resistance, and long starting time.
Bacteria ; Bioelectric Energy Sources ; Electricity ; Electrodes ; Polymers ; Water Purification

Exoelectrogenic microorganisms are the research basis of microbial electrochemical technologies such as microbial fuel cells, electrolytic cells and electrosynthesis. However, their applications are restricted in organic degradation, power generation, seawater desalination, bioremediation, and biosensors due to the weak ability of biofilm formation and the low extracellular electron transfer (EET) efficiency between exoelectrogenic microorganisms and electrode. Therefore, engineering optimization of interaction between exoelectrogenic microorganisms and electrode interface recently has been the research focus. In this article, we review the updated progress in strategies for enhancing microbe-electrode interactions based on microbial engineering modifications, with a focus on the applicability and limitations of these strategies. In addition, we also address research prospects of enhancing the interaction between electroactive cells and electrodes.
Bioelectric Energy Sources ; Biofilms ; Electrodes ; Electron Transport ; Electrons

Exoelectrogens are promising for a wide variety of potential applications in the areas of environment and energy, which convert chemical energy from organic matter into electrical energy by extracellular electrons transfer (EET). Microorganisms with different mechanisms and EET efficiencies have been elucidated. However, the practical applications of exoelectrogens are limited by their fundamental features. At present, it is difficult to realize the extensive application of exoelectrogens in complex and diverse environments by means of traditional engineering strategies such as rational design and directed evolution. The exoelectrogens with excellent performance in environments can be screened with efficient strain identification technologies, which promote the widespread applications of exoelectrogens. The aims of this review are to summarize the methods of screening based on different types of exoelectrogens, and to outline future research directions of strain screening.
Bioelectric Energy Sources ; Electricity ; Electron Transport

Anode is an important part of microbial fuel cell, its performance significantly affects the electricity generation of microbial fuel cells (MFCs). Nanomaterials have excellent properties, such as good conductivity and large surface area. Therefore, nanomaterials modified anode can effectively reduce the electrode resistance, increase the amount of microbial adhesion and improve the electricity generation of MFCs. In this paper, we introduced various nanomaterials modified anodes and summarized their effects on the output performance of MFCs. Finally, the prospect of modifying nanomaterials and technologies were discussed.
Bioelectric Energy Sources ; Electricity ; Electrodes ; Nanostructures

Bioenergy, as a renewable energy, is one of the best solutions to substitute part of fossil fuels. Based on the 6th World Bioenergy Symposium, this special issue includes latest reports and articles on the fields of bioethanol, biodiesel, microbial lipid, biofuel standard and aviation biofuels.
Bioelectric Energy Sources ; microbiology ; Biofuels ; microbiology ; Biotechnology ; instrumentation ; methods ; Ethanol ; isolation & purification ; metabolism

Microbial fuel cell (MFC) is a new technology that can recover energy from biomass with simultaneous waste treatment. This technique has been developed fast in recent years in combining with environmental techniques such as wastewater treatment, degradation of toxic pollutants and desalination. With the increase of solid waste, applying MFC in composting is promising due to its property of waste disposal with simultaneous energy generation. In this paper, the microbial community of MFCs during composting was summarized. Four major influencing factors including electrodes, separators, oxygen supplement and configurations on the performance of composting MFCs were discussed. The characteristics of composting MFC as a new technique for reducing solid waste were as follows: high microbial biomass resulted in the high current density; adaptable to different environmental conditions; self-adjustable temperature with high energy efficiency; the transportation of proton from anode to cathode were limited by different solid substrates.
Bioelectric Energy Sources ; microbiology ; trends ; Electricity ; Electrodes ; Refuse Disposal ; methods

More and more attentions have been being paid to seeking alternatives for fossil fuels. Bioenergy, as a renewable energy, is one of the best solutions. Bioenergy has been developed rapidly in China, which became the third largest producer and consumer of fuel ethanol. In order to promote the research of bioenergy technology in China, this special issue includes latest reports and articles on the fields of bioethanol, biodiesel, microbial lipid and biofuel system analysis.
Bioelectric Energy Sources ; trends ; Biofuels ; Biotechnology ; trends ; Conservation of Energy Resources ; methods ; Ethanol ; metabolism

The background and the importance of developing industrial biotechnology were illustrated, followed by a brief analysis on the driving effect of genomics and functional genomics. Seventeen papers covering metabolic engineering, fermentation engineering, industrial enzymes and biocatalysis are published in this special issue. These papers were briefly introduced to show the most recent developments of industrial biotechnology.
Biocatalysis ; Bioelectric Energy Sources ; Biotechnology ; methods ; trends ; Genetic Engineering ; methods ; Genomics ; methods ; Industrial Microbiology ; methods