Achieving a circular bioeconomy through fungal biorefineries for single‐cell protein production: advances, breakthroughs, and future directions

Abstract Waste valorization through fungal biorefineries represents a transformative and promising pathway for sustainable single‐cell protein (SCP) production, but it is yet untapped. This waste valorization strategy holds significant potential to enhance food security and promote environmental sustainability, particularly in developing nations where the attainment of these goals remains slow. At present, research is directed toward the upcycling of biodegradable waste streams for cultivating filamentous fungi, which can convert low‐value bioresources into high‐quality protein‐rich biomass that can serve as a competitive alternative to traditional protein sources. This review elucidates the recent technological developments in fungal biorefineries for SCP production through the valorization of copious biowaste streams, in alignment with the overarching circular bioeconomy framework. We critically evaluate: (1) innovations in strain selection, waste pretreatment, and fermentation technologies (e.g. gas fermentation and co‐cultivation); (2) bioprocess optimization strategies to enhance production yield and scalability; and (3) emerging commercial applications across diverse economies, including case studies from China and South Africa where SCP innovations are envisioned to spur job creation, economic growth, and improve food security in line with the 17 United Nations’ Sustainable Development Goals. Additionally, we discuss ongoing research and development efforts, particularly those that are pursued at higher technology readiness levels, that will pave the way for the industrialization of SCP innovations. Unlike prior reviews, we spotlight the unique and exquisite capabilities of fungal cell factories (e.g. lignocellulose degradation efficiency and low‐cost cultivation) and identify hurdles in downstream processing, regulatory framework, and consumer acceptance. By harnessing locally sourced biowaste streams through novel and scalable fungal biorefineries, the global community can move toward a sustainable and self‐sufficient protein production system.