Additive Manufacturing of Biomass–Fungi Composites: From Feedstock Formulation to Functional Performance

Abstract Biomass–fungi composites offer renewable, biodegradable, and energy-efficient alternatives to conventional petroleum-derived plastic materials. These composites are produced by combining lignocellulosic biomass with filamentous fungal mycelium, which naturally binds and interconnects biomass particles into products. Their mechanical, thermal, and acoustic properties can be tailored through fungal strain selection, substrate composition, and processing conditions, making them suitable for applications in packaging, construction, furniture, and insulation. The integration of biomass–fungi composites into additive manufacturing has further expanded their potential, enabling the fabrication of products with complex shapes. However, printing biologically active mixtures introduces unique challenges, including control of rheological behavior, maintenance of fungal viability, and optimization of interlayer bonding. This review summarizes recent progress in the bioink formulation, pre-/post-processing, and 3D printing of biomass–fungi composites, highlighting the relationships between feedstock preparation, printing parameters, and resulting structural and functional properties. Finally, it outlines opportunities to enhance printability, scalability, and emerging functionalities, providing a roadmap for advancing biomass–fungi composite materials toward industrial applications.