Pear, O. | Search bioRxiv

bioRxiv2025

Engineering Biohybrid Mycelium Fibers through Hierarchical Structuring and Biomineralization

Driven by the persistence of microplastics and an overdependence on non-renewable sources, mycelium materials have emerged as alternatives to traditional materials, owing to their sustainable production and versatility. Engineered living materials, composite material systems incorporating biological components to enable function, possess desirable regenerative properties but have yet to be fully applied due to their lack of strength versus synthetic or natural materials. We leverage two strategies used by nature to generate mechanical strength: structural hierarchy and biomineralization. We extrude a bioink composed of alginate and a modified strain of the fungus Aspergillus niger capable of silica mineralization, and modulate the morphology by the growth and processing conditions. Mineralization results in significantly stronger and stiffer dried fibers. We demonstrate their potential as textile materials through twisting and braiding to significantly increase the fracture strain. Our results show that mycelium morphology and mechanics can be tuned through mineralization, growth conditions, and processing.

bioengineering↗

bioRxiv2025

Uncovering the Design Rules for Sustainable Growth of Mineralized Mycomaterials

Mycomaterials, materials made from filamentous fungi, have several advantages over traditional materials, such as their genetic programmability and self-healing properties. However, their lack of mechanical strength and cost of production often constrain the applications they can be used in. In this work, we take inspiration from natural systems to overcome these challenges by elucidating design principles for mineralization-based enhancement of mechanical strength and synthetic lichen-based low-cost growth. We demonstrate that surface display of an enzyme from sea sponges, silicatein , on the hyphae of the filamentous fungus Aspergillus niger enables mineralization of polysilicate and that this does not impact fungal growth. We also show that this strategy can be extended to other silicatein variants and characterize how the degree of mineralization can be modulated. We then demonstrate that mineralization enhances the mechanical properties of the mycelium, including its tensile strength, modulus, and toughness. Finally, we show how these reinforced mycelia can be grown without external carbon sources using a synthetic lichen-based co-culture to facilitate low cost biomanufacturing. Together, our results lay the groundwork for the sustainable production of mineralized mycomaterials and create a new model system to study how mineralization impacts growth and mechanical properties. Significance StatementMaterials made from filamentous fungi, called mycomaterials, have several advantages over traditional materials, but their poor mechanical properties and relatively high production costs have limited their application. We elucidated design principles to enable tunable mineralization of fungal mycelium and have shown that it does not impact growth but significantly enhances mechanical strength. We have also shown that these reinforced mycelia can be grown without any external carbon in a synthetic lichen like consortia to minimize production costs. This work creates a novel experimental system to study how mineralization impacts growth and mechanical properties and will facilitate the broader application of mycomaterials in the future.

synthetic biology↗