Fungal-derived chitosan for active food packaging: Comparison to animal-derived chitosan, challenges, and future prospects of Ganoderma lucidum-derived chitosan

Chitosan is one of the most extensively studied biopolymers for active food packaging because of its excellent film-forming, antimicrobial, antioxidant, and biodegradable properties. However, the broader application of conventional animal-derived chitosan, primarily obtained from crustacean shells, such as shrimp, crab, and lobster shells, is constrained by seasonal raw material availability, chemical-intensive extraction, the potential presence of residual shellfish allergens, and increasing consumer demand for sustainable, animal-free materials compatible with vegetarian and specific religious dietary preferences. Consequently, fungal-derived chitosan, obtained from the cell walls of various fungal species, has emerged as a promising alternative, offering a renewable and potentially lower-environmental-impact source while exhibiting physicochemical and functional properties comparable to those of conventional animal-derived chitosan, which is predominantly obtained from crustacean shells. This review critically compares animal and fungal-derived chitosan, focusing on their sources, extraction methods, molecular weight (MW), degree of deacetylation (DD), and physicochemical and functional properties relevant to active food-packaging applications. The comparison highlights the advantages, limitations, and source-dependent characteristics that influence film formation, mechanical strength, barrier properties, and bioactive performance. Particular attention is given to Ganoderma lucidum (Reishi) as a fungal source of chitosan, with reported antimicrobial and antioxidant properties but with limited investigation into active food-packaging applications. By identifying these knowledge gaps, the review highlights both the broader potential of fungal-derived chitosan and the specific, underexplored potential of G. lucidum -derived chitosan as sustainable biomaterials for the development of multifunctional active food-packaging films. The review also identifies key knowledge gaps and future research priorities needed to facilitate industrial translation and support the development of sustainable, next-generation active food-packaging materials.