Abstract:

Objective: To investigate the effect of respective additions of selenium and cerium at various concentration levels on contents of polysaccharides and triterpene in fermentation supernatant and mycelia of Ganoderma lucidum. Methods: Ganoderma lucidum was statically grown for 30 d in shallow liquid medium containing various concentrations of sodium selenite or ammonium ceric nitrate. At the end of fermentation, the fermentation broth was harvested and separated into supernatant and mycelia to measure polysaccharide content in both of them by phenol-sulfuric acid method and ganoderic acid content in the mycelia by glacial acetic acid-vanillina method. Results: Added sodium selenite at the level of 40 mg/L to culture medium resulted in 42.3% and 10.6% increases of polysaccharides and ganoderic acid contents in the mycelia, respectively. An increase of 51.1% in polysaccharide content in the mycelia resulting from the addition of 15 mg/L ammonium ceric nitrate was observed, whereas ganoderic acid content exhibited a decrease. Respective additions of selenium and cerium resulted in an obvious increase of polysaccharide content in the supernatant. Conclusion: Respective additions of selenium and cerium to culture medium at an appropriate level significantly enhance polysaccharide contents in m fermentation supernatant and mycelia of Ganoderma lucidum, although added selenium increases ganoderic acid content, while added cerium decreases ganoderic acid content. To obtain high-quality fermentation supernatant and mycelia of Ganoderma lucidum, selenium and cerium should be added appropriately according to actual production requirements.

Key words: Ganoderma lucidum, sodium selenite, ammonium ceric nitrate, Ganoderma lucidum polysaccharide, triterpene, ganoderic acid