Schizophyllan (SPG) is a neutral β-glucan polysaccharide produced by the basidiomycete fungus Schizophyllum commune, characterized by its distinctive triple-helix architecture and potent immunomodulatory bioactivity.
Molecular Structure
Schizophyllan consists of a linear β-(1→3)-D-glucan backbone with β-(1→6)-linked D-glucose side branches occurring approximately every third glucose residue. While structurally analogous to scleroglucan, schizophyllan forms a more rigid and stable triple-helix conformation in aqueous environments. The polymer exhibits an average molecular weight of approximately 450 kDa and a specific optical rotation of +18 to +24°.
Under alkaline conditions or elevated temperatures exceeding 120 °C, the triple-helix structure dissociates into single chains; however, the native helical conformation can be restored upon neutralization or cooling. This reversible structural transition contributes to the unique functional properties of schizophyllan.
Production and Properties
Schizophyllan is produced extracellularly through the cultivation of S. commune in glucose-based media, typically maintained at 25–30 °C and pH 5–6. Following fermentation, the polymer is recovered by alcohol precipitation, filtration, and subsequent purification steps.
The resulting polysaccharide displays high water solubility, broad thermal and pH stability, elevated viscosity, and excellent biocompatibility. Additional properties include non-toxicity, biodegradability, film- and gel-forming capabilities, and resistance to oxidative degradation. The triple-helix conformation further enables self-assembly behavior and metal ion chelation.
Biomedical Applications
Schizophyllan exerts significant immunomodulatory effects through binding to the Dectin-1 receptor, leading to the activation of innate and adaptive immune responses. It has demonstrated antitumor activity against various cancers, including sarcomas, as well as antiviral, antibacterial, and anti-inflammatory effects.
Beyond immunotherapy, SPG is increasingly utilized as a functional biomaterial in drug and gene delivery systems, including nanogels and nanofibers. Its high biocompatibility and ability to support cell adhesion and proliferation also make it suitable for tissue engineering scaffolds and vaccine adjuvant formulations.
