Inonotus obliquus (Fr.) Pilat is a Basidiomycete, obligate parasite of birch trees. It is distributed in the northern hemisphere, in particular in subarctic areas. It is a common species of Finnish forests (1). The fungus produces a conk eruption from the bark, called Chaga, which is a renowned folk remedy. Polysaccharides possess a prominent role among its bioactive compounds (2). The exploitation of Chaga is hampered by conk slow growth. A promising cheaper alternative for Chaga polysaccharides production is mycelium submerged cultivation. For future nutraceutical implementation, and due to the different production method, polysaccharides obtained from submerged cultivation require throughout investigation and comparison with conk extract. In our study, a Chinese strain of I. obliquus was cultivated and polysaccharides were extracted with hot water. Polysaccharides were extracted from Chinese wild sterile conk, with the same procedure, and from Finnish sterile conk, as comparison. After purification, sugar content, monomer composition, and molecular weight of polysaccharides were determined. Our results showed that conk extracts contained low molecular weight polysaccharides, mainly composed of xylose. In contrast, mycelium polysaccharides were both of low and high molecular weight and consisted mainly of glucose. Differences between Finnish and Chinese conk extracts were noted as well. Aiming to increase the mycelium yield for polysaccharide extraction, sea buckthorn press cake was added to the medium. Its influence on fungal macromolecular composition will be the subject of future studies.

(1) Balandaykin & Zmitrovich, Int. J. Med. Mush., 17, 95 (2015).

(2) Zheng et al., Appl. Microbiol. Biotechnol., 87, 1237 (2010).