Isolation, purification, and structural elucidation of a water-soluble polysaccharide derived from Phellinus baumii Pilát mycelia

This study involved the successful production of mycelial polysaccharides by optimizing submerged culture conditions of <i>Phellinus baumii</i> Pilát. Then, the investigation focused on the composition and chemical structure of the water-soluble polysaccharide from <i>P. baumii</i> Pilát mycelia (PBMP) by extraction and purification. Specifically, this study indicated that a water-soluble PBMP fraction 1 (PBMP₁) was isolated from PBMP. Moreover, this study discovered a PBMP₁ isolated from PBMP, which was found to have the monosaccharide compositions comprised of fucose (Fuc), glucose (Glc), and galactose (Gal) despite the absence of proteins. Subsequently, the composition and structure of PBMP₁ were characterized using Fourier transform infrared (FT-IR) spectroscopy, periodate oxidation, Smith degradation, methylation reaction, gas chromatography-mass spectrometer (GC-MS), and Nuclear magnetic resonance (NMR). The composition and structure of PBMP₁ were characterized in this study, revealing an α-glycosidic bond conformational linkage with 1,4-Glc residues and 1,6-Gal residues forming the backbone. Additionally, a highly branched hetero-polysaccharide was identified with a non-reducing terminus of Fuc containing 1,3,4- and 1,4,6-Glc branching. The findings of this study offer valuable insights and information that can be utilized by researchers, manufacturers, and other stakeholders to advance the field of <i>P. baumii</i> Pilát product development. Moreover, these results have significant implications for future large-scale mass production and functional applications of PBMP₁ products.