Fungal biorefinery is a popular method for producing advanced fabrics but is currently limited to leather alternatives and similar by the sheet-based nature of most fungal materials. Biopolymers in the fungal cell wall, such as chitin and chitosan, are only soluble in harsh chemicals, making established extrusion-based yarn production systems expensive and hazardous. The Japanese art of Shifu is used to produce fungal chitin-β-glucan yarns of varying linear density from engineered fungal sheets, enabling the production of yarns. Yarn mechanical strength is influenced by sheet precursor grammage and can be tuned using various chemical modifications such as glycerol-based plasticization. Yarns hybridized with nanocellulose exhibited low strength, stiffness, and ductility, due to weak interfacing with fungal sheets. With mechanical properties outperforming commercial cellulose paper yarns and on par with cotton and viscose yarns, fungal yarns produced from engineered sheets of fungal biomass using Shifu techniques represent a viable yarn candidate for a broad range of applications, yet unachieved using fungi, such as textiles, upholstery, and carpets for the fashion and décor sectors.

Organic polymer-based composite materials with favorable mechanical performance and functionalities are keystones to various modern industries; however, the environmental pollution stemming from their processing poses a great challenge. In this study, by finding an autonomous phase separating ability of fungal mycelium, a new material fabrication approach is introduced that leverages such biological metabolism-driven, mycelial growth-induced phase separation to bypass high-energy cost and labor-intensive synthetic methods. The resulting self-regenerative composites, featuring an entangled network structure of mycelium and assembled organic polymers, exhibit remarkable self-healing properties, being capable of reversing complete separation and restoring ≈90% of the original strength. These composites further show exceptional mechanical strength, with a high specific strength of 8.15 MPa g.cm⁻³, and low water absorption properties (≈33% after 15 days of immersion). This approach spearheads the development of state-of-the-art living composites, which directly utilize bioactive materials to “self-grow” into materials endowed with exceptional mechanical and functional properties.