Current challenges and future directions in the green synthesis of nanoparticles using fungi

Fungi have historically played a significant role in advancing biotechnology and are now increasingly recognized as flexible platforms for eco-friendly nanoparticle production. Nonetheless, progress has been hindered by inconsistent methodologies, limited mechanistic understanding, and reproducibility issues. Unlike earlier reviews, this study comprehensively analyzes a decade of research (2015-2025) to link fungal species diversity, biosynthesis pathways, and experimental setups to nanoparticle formation. It highlights the crucial roles of enzymatic activity and secreted metabolites in determining nanoparticle shape and stability. The study demonstrates that variables such as culture medium, pH, incubation period, and downstream processes are not minor technical details but key factors influencing nanoparticle size, morphology, and stability. Additionally, there is a strong taxonomic bias toward a narrow set of filamentous fungi and a material bias toward silver, gold, and zinc, despite the broader biosynthetic potential of the fungal kingdom and the growing relevance of unexplored metals, including critical metals (e.g., Nb, Zr, and V). By combining mechanistic insights with advanced transcriptomic, proteomic, metabolomic, and genomic data, myconanotechnology can move toward a predictive framework based on metal stress responses, secreted biomolecules, and redox metabolism. Achieving this shift is critical to improving reproducibility, scaling up production, and developing rational approaches to the creation of fungal nanomaterials for biomedical, environmental, and industrial applications.