Heavy metal contamination and energy crisis are two of today's most alarming environmental issues. Biological, chemical, and physical techniques for treating metal pollutants in wastewater resources all have limitations, such as high energy needs and operational costs, extensive chemical consumption, and trash formation as a by-product. Among these drawbacks, the large quantity of energy required to treat wastewater corresponds with a global energy crisis caused by a variety of environmental changes that are now reshaping the globe. As a result, a great deal of effort has gone into finding a low-cost, low-energy way of extracting hazardous metals from industrial wastewater. Hazardous metals may result from manufacturing or other industrial processes. Metal discharge to water sources is mostly caused by the printing, paper, and metal production industries.

Microbial fuel cells (MFCs) have been identified as a potential technology for generating electricity and removing hazardous metals from industrial wastewater resources due to their sustainability and eco-friendly nature. MFCs include two electrodes—an anode and a cathode—along with a proton exchange membrane (PEM). The anode is responsible for providing enough space for bacterial growth and extracellular electron transfer to oxidize organic materials in wastewater and create protons and electrons. MFCs have lacked commercial viability owing to their poor efficacy while receiving much attention for their potential to produce renewable energy and remediate wastewater simultaneously. However, the instability and poor performance of organic substrates to bacterial populations is a key problem that requires additional investigation. Enough amount of energy for bacteria to increase the electrogenesis process may be found in suitable organic waste. Therefore, there is a hot topic to utilize the waste-derived organic substrate in the MFCs.

This Special Issue focuses on recent developments in MFC technology that involve the utilization of waste materials (carbohydrates-based materials such as sugar cane waste, fruit waste, food waste, etc.) as organic substrate. It aims to provide a forum for the communication of the most recent findings, challenges, and recommendations in the fields of biological and non-biological catalysts, advancements in fabrication and design of electrodes, waste-derived organic substrate, heavy metals remediation, reactor design, and scaling up the MFCs setup, MFCs types, operational mechanisms, and applications of MFCs. In addition, the developing trend of using natural waste materials (such as biomass, plant waste, etc.) as electrodes in the MFC technology to increase performance is encouraged. This trend aims to improve the efficiency of the technology. We invite academics/researchers to highlight future views and address issues of commercializing MFC technology, such as cost concerns or cost analysis, in their submissions. We welcome original research and review articles.

Potential topics include but are not limited to the following:

• Microbial fuel cells
• Waste material in MFC systems
• Design and configuration
• Bioelectricity generation
• Electro-active microbial role in MFCs
• Metal removal/remediation
• Biological and non-biological catalysts
• Natural organic substrates
• Waste-derived materials for electrode fabrication
• Challenges in MFCs commercialization
• A sustainable future perspective