Fungal Biotechnology for Sustainable Biocomposites: From Mycelium Growth to Material Translation

Fungal biotechnology has emerged as a promising platform for the development of sustainable biocomposites, leveraging the intrinsic ability of fungi to transform complex polymeric substrates into structurally integrated materials. This review critically evaluates mycelium-based biocomposites (MBCs), with particular emphasis on the relationships between fungal biosynthesis, substrate transformation, processing strategies, and resulting material properties. Key biochemical components, including chitin, chitosan, and β-glucans, are examined in terms of their molecular structures, biosynthetic pathways, and contributions to composite performance. The chemical modification of polymeric substrates during fungal colonisation, including enzymatic degradation, substrate remodelling, and interfacial bonding mechanisms, is critically discussed. The review further examines chemical functionalisation, hybrid reinforcement, and densification strategies for tailoring mechanical performance, thermal insulation, fire resistance, and durability, highlighting recent advances in processing-driven material optimisation. Applications in packaging, construction, insulation, environmental remediation, and functional materials are critically reviewed alongside sustainability considerations, including biodegradability, circularity, and life-cycle impacts. Finally, current challenges and future research directions are discussed, emphasising the integration of synthetic biology, advanced materials chemistry, and digital bio-fabrication to enable scalable, high-performance, and multifunctional MBCs.