Operational efficiencies and sustainable bioprocessing in electro-fermentation and microbial fuel cells.

The development of innovative bioprocessing technologies has resulted from the growing global need for sustainable forms of energy and environmentally friendly waste treatment. In this review, we focus on the combined electro-fermentation and microbial fuel cells, as they form a hybrid system that simultaneously addresses wastewater treatment, bioenergy production, and bioplastics. Even though microbial fuel cells produce electricity out of the organic waste by the use of electroactive microorganisms, electro-fermentation improves the microbial pathways through the external electrochemical management. The novelty of the review is that it compares the two technologies in detail and identifies the synergistic potential of the technologies as well as assesses the efficiencies of their operations, scalability, and impact on the environment. The research utilizing Scopus and PubMed directories was done by means of a systematic literature review that included 147 peer-reviewed experimentation and technology-oriented studies published during the period of 2012-2024. The main results lead to the conclusion that integrated systems imply significant increase in power densities (up to 2000 mW/m²), the enhancement of electron transfer efficiency (increased by 30-40%), large-scale production of useful products such as methane, hydrogen and organic acids. In spite of this promise, there are still difficulties regarding microbial stability, material costs, and energy balance. The review identifies the existing gaps and future opportunities, which include the development of novel electrode materials, the employment of better reactor designs and designer microbial consortia. The combination of such systems may become an interesting strategy of the next generation of biorefineries and have a good prospect to become a part of the circular economy and climate as a whole.