Fungal Secondary Metabolites in Bioelectrochemical Systems: A Bibliometric Analysis and Critical Review of Emerging Trends and Challenges for Sustainable Energy

The global energy crisis driven by an 80% reliance on fossil fuels and the urgent need to reduce greenhouse gas emissions demands the exploration of sustainable biotechnological alternatives. This study addresses a critical knowledge gap regarding the integration of fungal secondary metabolites into bioelectrochemical energy systems, as these compounds have traditionally been investigated for pharmacological purposes. The methodology involved a documentary analysis using the Scopus database (2000–2025), applying a search equation that combined terms such as “secondary metabolite”, “fungi”, and “bioenergy”. Data processing was conducted using R Studio (R 3.6.0+), VOSviewer (1.6.20) for collaboration networks, and Plotly Studio (v6.5.0) for interactive visualizations. Key findings revealed that redox mediators such as quinones and organic acids derived from Aspergillus niger enhanced electron transfer efficiency by 35%, achieving power densities of 1.2 W/m². Meanwhile, Penicillium chrysogenum reduced internal electrode resistance by 40%. Additionally, the “xeno-fungosphere” system achieved 97.9% herbicide removal and generated 9.3 µW/cm². Notably, biosynthesized bis-quinones were successfully applied in redox flow batteries, reaching a capacity of 1.58 Ah/L. In conclusion, the study identified a scientific shift from pharmacological applications toward energy metabolism and sustainability, positioning fungi as critical components for the future efficiency of bioelectrical technologies.