Isaac Karimi, Layth Jasim Mohammed, Ahmed M. Amshawee, Nahlah Fatehi Makki, Kosar Nazari, Helgi B. Schiöth
Mannans are structurally composed of β-(1 → 4)-linked mannose units, which are widely distributed in plant cell walls, yeast, and bacterial exopolysaccharides. Mannans have emerged as multipurpose biopolymers with significant industrial and biomedical potential. Celebrated mannans include guar gum, locust bean gum, konjac glucomannan, yeast mannans, and softwood glucomannans. This comprehensive review highlights the sources, structural diversity, extraction methods, physicochemical properties, safety, and functional characteristics. The major bioactivities of mannans, including immunomodulatory, antioxidative, and prebiotic effects, reflect their relevance in biopharmaceutical applications. Moreover, mannans serve as valuable raw materials for developing biodegradable films, hydrogels, and nanocomposites applied in sustainable materials and drug delivery systems. Despite promising applications, challenges related to their large-scale production, standardization, and functional optimization remain to be investigated. Future perspectives focus on integrating advanced biotechnological approaches and chemical modifications to enhance the functional versatility of mannans. Overall, mannans represent a sustainable, multifunctional biopolymer with expanding applications across food, pharmaceutical, and biomedical industries.