Abstract:

Four polysaccharides (P1, P2, P3, and P4) were prepared from the spent mushroom substrate of Cordyceps
militaris after the extraction with cellulase, fractional precipitation with ethanol and deproteinization with Sevag regent.
Their molecular weight distribution and monosaccharide composition were analyzed by gel chromatography and gas
chromatography-mass spectrometry (GC-MS). The polysaccharide P2 was further purified by Superdex 200 gel-filtration
column and its primary structure was studied by sodium periodate oxidation, Smith degradation, infrared spectroscopy as
well as nuclear magnetic resonance. The results showed that the fractional precipitation by ethanol in combination with
deproteinization by Sevag regent could provide preliminary purification for the polysaccharides, resulting in 3 relatively
pure polysaccharides (P2, P3, and P4) with molecular weight of 35.9, 9.4 and 3.7 kD, respectively. The structural analysis
demonstrated that P2 was a glucan with a chain mainly comprised of α-(1→4) pyran glucan. Both P3 and P4 were
heteropolysaccharides consisting of mannose, galactose and glucose with glucose being the main monosaccharide.

Key words: Cordyceps militaris, polysaccharides from spent mushroom substrate, separation and purification, structural analysis