Chemical Composition of the Moss Polytrichum Commune: A Focus on Structural Biopolymers.

The biomass of Polytrichum commune Hedw. (Polytrichaceae) moss demonstrates high pharmaceutical and biorefining potential, but its main structural biopolymers (cellulose, hemicellulose, and polyphenolic compounds) remain incompletely characterized. In this work, the method of nitric acid-ethanol extraction and dioxane extraction (Pepper's method) was used to isolate cellulose and lignin. XRD, SEC, FTIR, and Py-GC/MS were used for the biopolymer's characterization. The composition of hemicellulose was determined without prior isolation using HPLC analysis of the total biomass hydrolysate. The yields were: cellulose 23.0 ± 0.7%, hemicellulose (calculated as sum of mannose, galactose and xylose) 24.1 ± 0.5%, and dioxane-extractable polyphenolic fraction 8.0 ± 0.4% of dry biomass. The cellulose exhibits a low degree of polymerization (360) and moderate crystallinity (40.4% as determined by XRD). The hemicellulose is dominated by mannose and galactose (60% and 30% of non-cellulosic sugars), indicative of a galactomannan. The dioxane-extractable polyphenolic fraction has a low molecular weight (Mn~1100 Da) and an atypical H:S:G monomer ratio of 58:35:7, confirming its condensed non-lignin structure. These properties of moss biopolymers offer opportunities for comprehensive biomass processing and for further pharmacological evaluation of the polyphenolic fraction as a potential antioxidant source.