- Scleroglucan, often referred to as scleroglycan, is a high-molecular-weight extracellular polysaccharide produced by fungi of the genus Sclerotium, most notably Sclerotium rolfsii. It belongs to the family of β-glucans and is composed of a linear backbone of β-(1→3)-linked glucose units with a single β-(1→6)-linked glucose side chain approximately every third unit. This highly ordered yet flexible structure gives scleroglucan remarkable viscosity, stability, and gel-forming properties, making it valuable across food, pharmaceutical, cosmetic, and industrial applications.
- In its natural role, scleroglucan contributes to fungal survival by helping form protective extracellular matrices, enabling Sclerotium species to withstand harsh environmental conditions. For humans, its unique physicochemical properties have made it an important biopolymer. Unlike many natural gums, scleroglucan solutions remain stable over a wide range of temperatures, pH values, and salt concentrations. This resilience allows it to serve as a thickener, stabilizer, and emulsifier in formulations where other polysaccharides might degrade.
- In the pharmaceutical and biomedical fields, scleroglucan has received attention for its immunomodulatory and bioactive properties. As a β-glucan, it can interact with immune receptors such as dectin-1 and complement receptor 3 (CR3), activating macrophages, natural killer (NK) cells, and dendritic cells. These effects enhance innate immunity and have led to investigations into scleroglucan as an anticancer agent, vaccine adjuvant, and infection-fighting compound. Additionally, its ability to form stable hydrogels and viscous solutions makes it useful in drug delivery systems, where it can serve as a vehicle for controlled release of active pharmaceutical ingredients. Its biocompatibility also supports its use in wound healing formulations and tissue engineering scaffolds.
- In the food industry, scleroglucan is used as a stabilizer, texturizer, and viscosity modifier in products such as sauces, beverages, and dairy alternatives. Its high solubility and resistance to enzymatic degradation contribute to product consistency and shelf life. In cosmetics, it is incorporated into creams, lotions, and serums for its moisturizing and film-forming properties, which improve product texture and skin hydration.
- Scleroglucan also has important industrial applications. In enhanced oil recovery (EOR), it is used as a thickening agent in drilling fluids and flooding solutions, where its thermal and saline stability are critical. It is further applied in agriculture as a soil conditioner and in bioremediation efforts, where it helps stabilize emulsions and promote microbial activity in contaminated environments.
- From a scientific perspective, scleroglucan is notable for its ability to adopt triple-helical conformations in aqueous solutions, similar to curdlan and other glucans. This conformation is linked to both its rheological properties and its biological activity, making scleroglucan a model system for studying structure–function relationships in natural polysaccharides.
