Fungal Solid-State Fermentation for Circular Bioeconomy: Valorizing Agro-Industrial Waste Streams

Solid-state fermentation (SSF) is a sustainable and resource-efficient bioprocess for converting agricultural, forestry, and agro-industrial residues into high-value bioproducts, including industrial enzymes, organic acids, pigments, bioactive metabolites, food ingredients, animal-feed supplements, biofertilizers, and pretreated biomass. Filamentous fungi are particularly well suited to SSF because their hyphal growth enables efficient colonization of heterogeneous solid substrates while secreting diverse hydrolytic and oxidative enzymes capable of degrading lignocellulose, starch, proteins, and other complex polymers. As global efforts intensify to reduce waste generation, improve resource efficiency, and promote circular bioeconomies, fungal SSF has emerged as a promising platform for sustainable biomanufacturing. Recent advances in bioreactor design, omics technologies, systems biology, synthetic biology, strain improvement, and artificial intelligence-driven process optimization are further expanding the industrial potential of SSF.Despite these advances, large-scale implementation of SSF remains challenging. Heat and mass transfer limitations, substrate heterogeneity, moisture variability, contamination risks, oxygen gradients, and incomplete understanding of fungal physiology and microbial interactions continue to affect process reproducibility and product yield. Moreover, many studies remain confined to laboratory-scale experiments using single substrates, limiting their industrial relevance. Greater integration of downstream processing, product recovery, techno-economic analysis, life-cycle assessment, and regulatory considerations is needed to facilitate commercial adoption. Emerging questions include how fungal metabolism can be optimized for diverse lignocellulosic feedstocks, how microbial co-cultures and synthetic consortia can enhance substrate conversion, and how digital monitoring, machine learning, and predictive modeling can support robust scale-up and process control.This Research Topic aims to highlight recent advances in fungal solid-state fermentation as a versatile platform for sustainable bioprocessing and valorization of renewable biomass. By bringing together expertise in fungal biotechnology, microbial physiology, bioprocess engineering, substrate science, systems biology, downstream processing, and sustainability assessment, the collection seeks to bridge fundamental research with industrial applications that support the transition toward a circular bioeconomy.We welcome original research articles, reviews, mini-reviews, perspectives, and methods papers addressing, but not limited to, the following themes:*Fungal valorization of agricultural, forestry, food-processing, and agro-industrial residues*Industrially relevant fungi, including Aspergillus, Trichoderma, Rhizopus, Penicillium, and emerging fungal species*Novel solid-state bioreactor configurations, process scale-up, and reactor engineering*Optimization of substrate composition, moisture content, aeration, inoculum development, and fermentation parameters*Production of industrial enzymes, organic acids, pigments, bioactive compounds, food ingredients, feed additives, biomaterials, and biofertilizers*Microbial co-cultures, synthetic microbial consortia, and sequential fermentation strategies*Omics approaches, metabolic engineering, systems biology, and synthetic biology for strain improvement*Artificial intelligence, machine learning, biosensors, imaging technologies, digital monitoring, mathematical modeling, and process control*Product recovery, purification technologies, techno-economic analysis, life-cycle assessment, and sustainability evaluation*Industrial case studies, commercialization strategies, regulatory aspects, fungal SSFThis topic welcomes Original Research, Reviews, Mini Reviews, Systematic Reviews, Methods, and Perspectives. Topic editors: Rita De Cássia Mendonça De Miranda, Rajeshwari Negi, Dr Maria Tuohy Source: https://www.frontiersin.org/research-topics/85271/fungal-solid-state-fermentation-for-circular-bioeconomy-valorizing-agro-industrial-waste-streams