Polysaccharides from edible fungi mycelium: a review on extraction, characterization, bioactivities, and biosynthetic mechanisms

Polysaccharides derived from the mycelium of edible fungi (MEF) are structurally diverse and biologically active macromolecules, garnering extensive attention in functional foods, pharmaceuticals, and biomaterials. Despite the emerging growth in MEF polysaccharide research, the available literature focuses primarily on reviews on specific polysaccharides, necessitating an urgent need for a comprehensive summary of MEF polysaccharides to provide readers a systematic overview of current advancements in this field. This review systematically elaborates recent advances in MEF polysaccharide research, focusing on their extraction techniques, structural characterization, biological activities, and biosynthetic mechanisms. This review analyzes the effects of various extraction techniques on MEF polysaccharides and also explores the relationship between their structural characteristics and biological activities, highlighting that the complexity of these structures is crucial for determining their functional diversity. Moreover, the biosynthetic mechanism of MEF polysaccharides is discussed, revealing that regulating enzyme activity, particularly glycosyltransferases, can improve biosynthetic efficiency. Despite promising applications, challenges remain in optimizing extraction sustainability, scaling production processes, and deepening the mechanistic understanding of bioactivity. This comprehensive overview aims to strategically guide future research toward high-value applications and fundamental advances in fungal polysaccharide science.