Advancements in bioelectrochemical systems: Electrogens and methanogens behaviour, stress adaptation, and artificial intelligence-driven approaches for sustainable bioenergy

Microbial fuel cells (MFCs) and microbial electrolysis cells integrated anaerobic digestion (MECs-AD) are the emerging technologies of bioelectrochemical systems (BES) that enhance bioenergy production from bio(mass)waste. This review has been dedicated to the understanding of technical and biological aspects of microbes (i.e., electrogens and methanogens) in MFCs and MECs-AD. A key focus lies in elucidating the bioelectrochemistry of BES, complex microbial behavior, and strategies for microbial inoculation (such as pure strains, mixed consortium, genetic engineering, and bioaugmentation) as mono-cultures and co-cultures. Approaches for methanogen suppression in MFCs and electrogens enhancement in MECs-AD systems are addressed systematically. The synergy between electroactive bacteria, methanogenic archaea, and nanowires in electrogens of BES is discussed. The application of stress (e.g., salinity, temperature fluctuations, pH extremes, hydraulic/shear stress, electromagnetic fields, and chemical inhibitors) to stabilize functional microbes is also explored. The implementation of mixed stresses on BES is recommended to be beneficial in stabilizing microbial communities. Highlights the artificial intelligence (AI) driven strain design and machine learning (ML) advancements in BES. Neural networks and random forest algorithms can predict gene knockouts/insertions to maximize electron transfer. Therefore, further research is needed to implement genetically modified strains using AI and ML algorithms. The review's findings underscore the need for continued study at the intersection of microbial ecology, materials science, and computational modeling to unlock the full potential of BES systems.